# IV Components Used to Calculate Child Support Amounts

## A. Introduction

As described in Chapter II, there are two fundamental components to the construction of any child support formula.

The first component is the approach used to develop the “expenditures on children” that will be shared between the parents. It answers this question: “What are the financial amounts that are going to be used in the formula that approximate what parents spend on their children?”

The second component is the method used to apportion those expenditures between the parents. It answers the question “Once you have an amount that represents what parents spend on their children, how are the calculations constructed in the formula to share those expenditures between the parents, to arrive at a child support amount?”

The purpose of this chapter is to describe and summarize how the ten jurisdictions incorporate these two core components into their formulas.

To complement the various sections, supporting details have been included in Tables 4 and 5 at the end of this chapter. As well, the summaries for each jurisdiction included in this review can also be consulted in Volume II of this report.

## B. Approaches to Estimating Expenditures on Children

Although there has been a significant amount of discourse on the various methods to measuring child-rearing expenditures for the purposes of child support guidelines, economists do not agree on a preferred methodology.77 Thus with no “perfect method” available for expressing expenditures on children, it follows that jurisdictions have used different approaches in their child support models.

The three methods used by the sample of ten jurisdictions to estimate expenditures on children are described below.

### 1. Expenditures on children78

The determination of actual expenditures on children using this method is defined as the difference between expenditures in a married or cohabiting couple household with no children, versus a married or cohabiting couple living in a similar (in terms of combined family income levels, number and of age of children) household with children. In simple terms, this approach is called a “marginal cost” methodology with the difference in the amounts of expenditures in these two families being attributed to the cost of having children. It is this difference in the amount of expenditures that becomes the “cost of the child” that is used in the formula calculations. The data that underlies this methodology is derived from national expenditure surveys on what families of different sizes and compositions spend on various items in their family households. These surveys are conducted by government agencies responsible for the collection and dissemination of national statistics. The number and age of children, and level of income for both parents can also be disaggregated in the data sets.

As well, because the data in the expenditure surveys are robust and detailed, it is possible to disaggregate expenditures on various items that could, later on, be added back into the formula calculations – such as childcare or tuition costs. This approach provides the flexibility to move from the determination of an amount that represents the average costs of a child to an approach that determines the costs of basic items for a child, plus any add-ons for extraordinary items, if relevant given the family circumstances.

This approach has been criticized for not reflecting the expenditures in a single-parent household.79 However, the counter argument has been that since many single-parent families live in poverty, the data derived from single-parent families would be too low, resulting in child support amounts that, on average, would not be representative of the average family. Another argument against using single-parent expenditures is that the use of intact family expenditure data is more reflective of the expenditures on children over the life of a child support order. This is because both the paying and receiving parents are likely to reside with new partners at some period following their family breakdown80 and thus have expenditures more reflective of intact family patterns of spending.

### 2. Budget-based approach or a basket of goods methodology

Using this methodology, expenditures on children are derived by costing out the individual items that children are deemed to need, such as food, shelter, clothing, activities and transportation. The average of these expenditures for all children is then determined and the total of these expenditures is then used as the expenditures for the child in the formula calculations. These expenses can be generated for the age and gender of the children. Government agencies responsible for the collection and dissemination of national statistics are the mandated authority that collects these budget-based data. As well, as the individual items are identified and the costs determined, it is possible to disaggregate selected elements, remove them from the average costs and later, depending on the family circumstances, add them back into the calculations for the child support amount. This approach has been criticized for understating the expenditures for children in middle to higher income families, as the costs are usually based on a basket of goods for basic needs.81

### 3. A basic needs approach

Using this approach, the first step is to determine what expenditures are required to meet the basic needs of the child. In most cases, a jurisdiction will rely on low-income measures and the financial amounts required to meet the basic needs of children in low-income families. Again, these types of data are obtained from local, regional or national agencies that are responsible for measuring and disseminating information on low-income families and are usually used to set welfare or social assistance payment levels in the relevant jurisdiction. While similar to the basket of goods approach above, it differs from it in that the focus is on low-income families while the basket of goods relies on expenditures from families at all income levels.

## C. Approaches Used to Estimate Child Expenditures in the Jurisdictions

Table 4 outlines the approach each jurisdiction has adopted to incorporate expenditures on children into their formula, as well as the source of their expenditure data.

The approaches used by the ten jurisdictions are as follows:

### 1. Actual expenditures on the child

Seven of the ten jurisdictions82 use a guideline that incorporates actual expenditures on children. The expenditure data that form the basis of their formula are extracted from national household surveys administered and collated by national statistical agencies on an annual basis.83

### 2. Budget-based approach

In Sweden and Norway, the methodology underlying their model is based on what a family would spend on various items for their children. Both use average amounts for various items based on data collected by their respective national consumer agencies. In both jurisdictions, separate budget costs for such necessities as food, clothing, housing, leisure activities, etc., are also provided with the total of these expenditures being used as the basis of their child support amounts. In Sweden, parents may also opt to use their own actual expenditures based on what they have historically been spending on their child to assist in determining a child support amount. Norway also separates out expenditures on housing and supervision (childcare) costs, with the latter being actual expenditures reported by the parents. The actual costs of these two items are then added to the costs of the child in the calculation of the final award.

### 3. Basic needs of the child

Delaware is the only jurisdiction that uses this method for determining expenditures on children. In this state, the methodology for how expenditures are determined reflects their guidelines’ objective: the basic needs of the child are to be met first (after the basic needs of the parents are met)84 before the child is allowed to share in any excess income of both parents. To achieve this objective, their formula includes a two-step calculation. The first step is to determine an amount that represents the child’s basic needs. This is achieved by using expenditure data based on the annual United States federal poverty line amounts for a single person with one or more children. The second step (see below for a discussion of their apportioning approach) involves the calculation of a Standard of Living Adjustment that allows the child to share in any excess income the parents may have after both their and their child’s basic needs are taken care of.

All ten jurisdictions have used the same methodology to determine what numbers are to be used for their expenditures on children over the life of their child support models. With the exception of Norway and Sweden – which use a budget-based approach to determine the expenditures – none of the jurisdictions have changed their percentages (if using a fixed percentage model) or amounts (if using an income shares model) in any substantial way.

In two jurisdictions (the United Kingdom and Wisconsin), they have not revised the percentage of income rates since the inception of their guidelines based on the continued assumption that the proportion of money that parents spend on their children does not change over time.

Four jurisdictions (Australia, New Zealand, Vermont, and Illinois) have placed their effort on improving the quality of the research and information to ensure their expenditure data are up to date and comprehensive. They have been assisted by their respective national government organizations responsible for these data to improve their breadth and quality considerably over time. Although the results of the expenditure data derived from the national organizations are reviewed regularly to look for trends and changes, the amounts or percentages included in the guidelines have not changed, although depending on the jurisdiction, adjustments have been made on how the amounts are to be shared based on changes to the various factors considered in the formula calculations.

For the remaining four jurisdictions:

• Norway and Sweden have always used current, itemized costs for children. Thus, the amounts used in their guidelines are updated annually and are based on national data collected by a government agency.
• In Delaware, their amounts are based on federal poverty data and as those amounts change, the amounts used in the guidelines are also updated to reflect these changes.
• France has just introduced such tools as an online calculator to assist parents in the determination of child support amounts. The online calculator includes expenditures for children that have been derived using recent expenditure data on children to generate the percentages of income that is incorporated into this tool. However, as their experience with these guidelines is very recent, no adjustments have been made to date.

## D. Use of Expenditures in the Formula

Once a jurisdiction has chosen the method to determine the expenditures on the child that will be used in the formula, the next step is to determine how it will be used and displayed in the calculations themselves. An analysis of the jurisdictions reveals that the way expenditure amounts are displayed differs by jurisdiction.

### 1. Variations in how the expenditure data is utilized and displayed

Those jurisdictions that use actual costs as expenditure data, in accordance with their income shares model (New Zealand, Australia, Illinois and Vermont), display the expenditure costs in lookup tables that are contained in their child support legislation and provided on their websites.85

In the jurisdictions that use a fixed percentage of income model (Wisconsin, the United Kingdom and France), the expenditure data are shown as percentages of income. These percentage amounts are then applied to the paying parent’s income in the calculation of child support amounts. Wisconsin and the United Kingdom provide their percentage of income models in their legislation.

For Norway and Sweden, the budget items used to determine costs of children that are considered in the formula calculations are provided, and the amounts are pre-filled in the online calculators (or worksheets) used to assist parents and lawyers when determining child support amounts.86 The expenditure data are provided by their respective national consumer agency and are based on average costs. It should be noted that in Sweden, if parents are in agreement, they also have the option of using the actual amounts that they spend on their child instead of using the pre-filled amounts.

As mentioned above, Delaware’s expenditure approach is based on the amount that reflects the basic needs of a child. To arrive at the appropriate amount, the amount of the basic need is set as a proportion of the self-support allowance87 amount, which is based on data from the United States’ Federal Poverty Registry. The basic need amount consists of two components – a “per child” amount, which is multiplied by the number of children, and a housing amount, which is the same regardless of the number of children. Both components are approximately 25% of the self-support allowance. If there is more than one child, the “per child” amount is multiplied by the number of children.

### 2. Variations in the level of detail in the expenditure tables

The majority of jurisdictions present their expenditure amounts in tables or worksheets. These tables are presented to assist parents using one or more of the following characteristics: the age and number of the children, the level of income of the paying parent, or the combined income of both parents.

The extent to which the jurisdictions provide further breakdowns in the categories is related to the method they use to determine expenditures on children. Those jurisdictions that determine expenditures using a budget-based approach present the expenditure data disaggregated by more family characteristics.

• Age of the children

Six of the jurisdictions do not break down their estimated amounts on expenditures on children by the age of the children.88 New Zealand and Australia use the same age breakdown, consisting of two categories: 0-12 years of age, and 13 years and older. Norway and Sweden (the two budget-based jurisdictions) display their expenditure data by multiple age categories. Norway uses 5 age bands: 0-5 years, 6-10, 11-14, 15-18, and 19 years old. Sweden uses age bands that are very narrow, almost attributing costs to the child in an age specific manner. (Note: Sweden is the only jurisdiction to differentiate expenditures on children by gender of the child.)

• Number of children

Seven jurisdictions89 display their expenditure data by the number of children, while the two jurisdictions using the budget-based approach (Norway and Sweden) display expenditures “per child”, and thus child support may be calculated for any number of children.

In the United Kingdom, France, New Zealand and Australia, expenditure data are categorized by one to three or more children. Wisconsin and Delaware display data that allows up to five or more children. Finally, Illinois and Vermont provide expenditure data in their tables for one to six or more children.

• Level of income

The degree to which jurisdictions display their expenditure data by income level depends on the apportioning method that underpins their formula and even within those, there are differences.

In four of the income shares models (Vermont, Illinois, Australia and New Zealand), the income level amounts that are displayed reflect combined family income – as both parents must provide their income information to complete the calculation, and it is their combined income that is used to find the expenditure amount in their tables of expenditures. Vermont and Illinois display the most income increments, which are in bands of \$50 monthly combined income increments. Australia and New Zealand use five broad categories of income that are based on recent earnings data (average weekly earnings for male workers) and are in multiples of five (.5, 1.0, 1.5, 2.0 and 2.5 times earnings data). While Vermont and Illinois display a considerable amount of detail in their tables of expenditures, Australia and New Zealand, while using broader categories, provide more detailed tables of expenditures based on income on their websites.

In jurisdictions where the formula is based on a fixed percentage of income model (Wisconsin, the United Kingdom and France), only the paying parent’s income is necessary. Consequently, expenditures are expressed as a percentage of their income. However, these models differ slightly from one another as well. For Wisconsin, their model includes formulas that differ by the level of income of the paying parent: they have a low-income formula (income is between 75% and 150% of the Federal Poverty Guidelines for a single person) and a high-income formula (when income is above \$7,000). In the United Kingdom, the model includes four bands of income, with different percentages within each band. Finally, France uses a number of income categories in its table of child support amounts, and the income levels are displayed in 100-euro increments.

Finally, in Sweden and Norway, the two remaining income shares models, because each case is calculated using child specific costs, there is no need to provide breakdowns of these costs by income level.

## E. Approach Used to Apportion the Amount between the Two Parents

Once an expenditure method to estimate the costs of children has been chosen, these costs must then be apportioned between the two parents to determine a child support amount. How each model uses the incomes of both parents in the calculations differs.

To summarize, there are three basic models to apportion the costs, as outlined in Chapter II. They are:

Income Shares: The expenditures on the children are shared in proportion to the parents’ share of the combined family income. This model necessitates the collection and use of income information from both parents to calculate the amount of child support. In straightforward circumstances such as when the child lives the majority of the time with one parent, the other parent will pay the other parent their respective amount from the calculations in the form of child support.

Fixed Percentage of Income:90 The expenditures on children are expressed as a percentage and only requires the income of the paying parent. That income is multiplied by the percentage to generate a child support amount.

Melson Formula: The distinguishing feature is a two-step apportioning of the incomes of both parents to arrive at the appropriate child support amount. The first step requires the incomes of both parents to complete the calculations; they calculate their proportional share to meet the basic needs of the child – which is why it appears very similar to the income shares model. However, unlike other income shares models, included in the formula is a calculation that only requires the income of the paying parent. This is where the Melson formula is based on a fixed percentage model. As part of the formula calculation, a percentage of the paying parent’s excess income (after basic needs of the child and the paying parent are subtracted) is used in the determination of a standard of living adjustment. This amount allows the child to share in the standard of living of the paying parent.

As Table 5 indicates, six jurisdictions have models that are based on the income shares approach (Australia, New Zealand, Norway, Sweden, Illinois and Vermont). Three jurisdictions (the United Kingdom, Wisconsin and France) have child support models based on a fixed percentage of income model. Delaware uses the Melson model.

## F. Summary

Most jurisdictions conduct economic research using data based on actual expenditures collected by their relevant national government agency. The results of this research on expenditures on children in families provide the basis for including the expenditures in the formula calculations and are presented as amounts or percentages, depending on the formula type. For the seven jurisdictions that use actual expenditures on children, they can be classified as using a “continuity of expenditures” approach91 - the underlying premise being “...that children should continue to receive the same amount of expenditures they would have had [if] the parents never separated or divorced”.92 They are not, nor do they purport to be, actual expenditures, but rather are proxies for the expenditures on children in their jurisdictions.

The jurisdictions that use a budget-based approach to determine expenditures also obtain their data from a national government agency. The expenditures included in their guidelines are based on “the average costs required to meet the needs of the child” as opposed to “what families spend on their children”. However, in both of the jurisdictions that use this approach (Norway and Sweden), parents have the option to use their current itemized costs for their child.

All ten jurisdictions have used the same methodology to determine what numbers are to be used for their expenditures on children over the existence of their child support models. With the exception of Norway and Sweden, which use a budget-based approach to determine the expenditures, none of the jurisdictions have changed their percentages (if using a fixed percentage model) or amounts (if using an income shares model) in any substantial way.

That being said, regardless of the method used to develop expenditure data, most jurisdictions review their expenditure data periodically to ensure their data are of high quality to best reflect expenditures on children.

The majority of jurisdictions display their expenditure amounts in the form of tables or in worksheets designed to assist parents and child support officials to complete the formula calculations. The level of detail provided in the tables or worksheets on the income levels of the parents and on the ages and number of children depends on the method used to determine the expenditures. These jurisdictions also have their expenditure data or their proxies (e.g., in percentages of combined income) in their child support legislation.

The majority of jurisdictions (seven)93 have models that are based on an income shares approach to apportioning the costs between the parents to determine a child support amount. This requires using the incomes of both parents to calculate the child support amount. The expenditures of the child are then divided in proportion to each parent’s income. A stated advantage of the incomes shares model is that it “...can more readily factor in and address a larger variety of case circumstances than the traditional percentage of income model. This includes circumstances where the custodial parent has more income than the non-custodial parent, shared-parenting time, and other circumstances.”94

The remaining three jurisdictions95 have models that are based on a fixed percentage of income model96, which requires only the paying parent’s income. A stated advantage of the percentage of income models “...is (they are) often seen as easier to implement, administer and understand.”97 However, when the parenting time is either shared or split, the income of both parents is required to complete the formula calculations. Thus, the method underpinning the calculation becomes an income shares approach. Consequently, these three jurisdictions use both the percentage of income model (in sole custody situations) and the income shares model (in split and shared custody situations).98

Table 4: How are child costs determined?
Jurisdiction Basis of expenditures: child’s needs, expenditures in families, basket of goods. Source of expenditure data Way they are represented Tools and/or tables and their updating

United Kingdom

Expenditures on children are expressed as “percentages” of costs of children in an intact family.

The current child maintenance rates (percentages) were developed in the 1980s and have not changed.

The United Kingdom Office for National Statistics produces data on average weekly household expenditures on goods and services in the United Kingdom by region, age, income, economic status, socio-economic class and household composition. The data collected by this agency were instrumental in the determination of the rates to be used when the guidelines were first introduced. The rates have not changed, as the assumption is that the proportion of costs that parents spend on children does not change over time.

Percentages of Household Average Weekly Income that vary based on number of children (1, 2, 3 or more) and level of paying parent income. United Kingdom has five bands of income levels of the paying parent.

Child Maintenance Service provides information on its website with the “rates” to be used based on the income of the paying parent.

Australia

Actual expenditures on children are used. The approach is based on a “marginal cost” model that compares expenditures of two sets of equally well-off households – one set consists of two-parent families with children and the second set consists of couples without children. The difference in expenditures is assumed to be the cost spent on child rearing.

The current approach to determining the expenditures on children relies on studies on the “costs of children” conducted in 2005 by the Ministerial Taskforce on Child Support. The Taskforce recommended that the costs of children used in the formula should be expressed as a percentage of the combined income of the two parents (after their respective self-support allowances have been subtracted).

Percentages of Household Average Weekly Income that vary with parents’ combined child support income level, number and age grouping of the children.

• Table of Percentages in Child Support (Assessment) Act 1989. Schedule 1.
• Costs of the Children Table on website with annualized income levels and child support amounts.
• Income categories are updated annually.
• Cost Percentage Table that consists of a lookup table that converts a parent’s actual percentage of time with care of the child to their Cost Percentage.

Note: Costs themselves are represented as percentages of parents’ combined income rather than amounts, thus do not require updating. Costs will increase as the standard Male Total Average Weekly Wage (MTAWE) increases.

New Zealand

To derive the information contained in the Child Expenditure Table in Schedule 3 of the CSA, the actual amounts of expenditures on children determined in the 2009 study have been converted to percentages of income. The percentages represent marginal expenditures, which indicates how much each additional dollar of child support income in an “average weekly earnings” band is to be treated as expenditures on children. The Table contains percentages based on three variables: income, age of children and number of children.

Statistics New Zealand's 2006-07 Household Economic Survey (HES).

Child Expenditure Table Percentages of Household Average Weekly Income that vary with: parents’ combined child support income level, number and age of children.

• Table of Percentages in legislation, Schedule 3 of the Child Assessment Act of 1991.
• Table on website with annualized income levels and child support amounts by level of parents’ combined income and age groups of children.
• Income categories are updated annually.
• Care Cost Percentage Table lookup chart to convert a parent’s actual percentage of time with care of the child, to their Care Cost Percentage.

US: Vermont

Actual expenditures on children are used. The approach is based on a “marginal cost” model that compares expenditures of two sets of equally well-off households – one set consists of two parent families with children and the second set consists of couples without children. The difference in expenditures is assumed to be the cost spent on child rearing.

2004-2009 USDA Consumer Expenditure Survey administered by the Bureau of Labour Statistics.

Vermont Table of Intact Family Expenditures on Children:
Expenditures on children covered by monthly combined parents’ income and number of children.

Lookup Table is available in Legislation.
Vermont Table of Intact Family Expenditures on Children
These expenditure data are reviewed for accuracy and currency every four years during Vermont’s quadrennial review.

US: Wisconsin

The guiding principle in Wisconsin is the concept of “continuity of expenditure”. This means that children should not be adversely affected because their parents do not live together. Thus, estimates of expenditures on children in intact families are the basic comparison point for the “costs” of children.

Economic research undertaken by Wisconsin in the 1980s concluded that the proportion of income devoted to a first child varies from between 16 to 24% for one child in intact families. It also found that the share of income spent on the second and third child was about half of what was spent on the first. This research produced the percentage standard that Wisconsin uses today.

Wisconsin converted the household expenditures on children to percentages of income. These are represented as the percentage of income of the paying parent in each of the six formulas (and the receiving parent for shared placement (custody) cases).

The percentage standard is the same set of percentages used since the inception of Wisconsin’s guidelines.
All six formulas are detailed in their legislation, Chapter 49 Department of Children and Families 150 Child Support Percentage Of Income Standard.2018, along with sample case scenarios.

US: Illinois

Actual expenditures on children are used. The approach is based on a “marginal cost” model that compares expenditures of two sets of equally well-off households – one set consists of two-parent families with children, and the second set consists of couples without children. The difference in expenditures is assumed to be the cost spent on child rearing.

USDA Consumer Expenditure Survey administered by the Bureau of Labour Statistics. Amounts for Illinois were generated in 2012 and updated in 2017 using the consumer price index amounts. Amounts are only provided for one to three children. An equivalence scale approach is used to extrapolate applicable amounts for 4, 5 and 6 children.

Income Shares Schedule Based on Net Income
Schedule contains parent’s monthly combined net income by number of children.

Lookup table available in Legislation:

Income Shares Schedule Based on Net Income.

Expenditure data are examined every four years during Illinois’s quadrennial review.

US: Delaware

Two expenditure types. The first is an amount that is deemed to meet the children’s basic needs. The second is an amount based on the amount of excess income of the parents after meeting their basic needs. It is called a Standard of Living Adjustment (SOLA) as it uses a percentage of the available income to determine an additional amount to be added to share of the basic needs amount. Percentages are based on the proportional costs of children in intact families.

Federal Poverty Guidelines as published in the Federal Register by the US Department of Health and Human Services.

Two components: the first component is a “per household component”. This amount is set at 25% of the Self Support Allowance for the parent - minus \$72 per month. This is an amount that is set regardless of the number of children that are the subject of the award. The second is a “per child” component. This amount is currently set at 25% of the Self Support Allowance for the parent plus \$24. To determine the Total Primary Support Allowance, the number of children is multiplied by the “per child component” (\$310 per month). Then the “per household amount” (\$210 per month) is added.

No tables – all information provided is contained in the online calculator

Sweden

Basket of goods approach. Amount is determined by adding up standard items such as costs for food, clothing, hygiene, shoes, leisure time and fun activities, etc.

Two options: If parents agree, parents can decide the monthly expenditures that are spent on the child, or they can use the amounts provided by the Swedish Consumer Agency that represent average costs for these items for children, broken down by age and gender of child.

“Costs for basic needs” includes: average monthly amounts spent on children in Sweden for food, hygiene, clothes and shoes, leisure time and fun activities, mobile phone costs (for children over age 11), and insurance. Other non-standard expenses may be added to these costs and can include: childcare expenses, expensive recreational activities, any school fees, costs related to a special diet, and anything else not included in the base costs. All these “costs” are added together to provide the monthly costs of the child.
Subtracted from the total costs above is the standard monthly Child allowance. If the child has other income, it is also subtracted from the costs calculated above.
Costs are on a per child basis and vary by age and gender of the child. The online calculator allows for an unlimited number of children to be entered.

No table provided but amounts are pre-filled in online calculator.

Parents may enter their own amounts for the various items instead of using the pre-filled amounts from the Swedish Consumer Agency.

Norway

Average budget amounts of children in intact families across five age categories. Costs include consumption, building and supervision (childcare) expenses.

Both the individual-specific and the household-specific expenses are determined on the basis of an annual reference budget for consumption expenditures on children designed by the National Institute for Consumer Research.

Costs are provided separately for consumption, building and supervision.

Budget costs are broken down according to five age groups: (0-5 years, 6-10 years, 11-14 years, 15-18 years, and 19 years and older).

The child benefit is subtracted from the above costs.

Only the aggregate costs are provided for consumption and building costs.

France

The expenditures on children are based on average costs of children in intact families. These average expenditures are converted into the percentages of expenditures on the child that the average intact family would spend.

Fixed percentages of income are based on economic research in France on expenditures in intact families. Percentages are the same for all incomes but vary with number of children and amount of time spent.

Percentages of income that decrease as number of children increases and the amount of time spent with the child increases.

One lookup Table of Child Support Amounts provided on website displaying percentages by parenting time and number of children.
The Table is discretionary, and it is not in legislation.

Table 5: Current Apportioning Approach Used to Determine the Child Support Amount
Country / US State Apportioning approach (fixed percentage, income shares, or Melson model) Basic approach or are there modifications?

United Kingdom

Fixed percentage of income

Modification: Five “percentage of income formulas” are available depending on the level of income of the paying parent and their ability to pay.

Australia

Income Shares

Modification: Each parent’s percentage of time spent with the child is subtracted from his or her respective income share percentage. The parent with the “positive” result is the liable (paying) parent. The paying parent’s final percentage is multiplied by the expenditure amount to produce the child support amount. The child support amounts are calculated on a per child basis to account for different ages of the child (thus different costs) and/or different parenting time arrangements. These amounts are added together to produce a final monthly child support amount.

New Zealand

Income Shares

Modification: Each parent’s percentage of time spent with the child is subtracted from his or her respective income share percentage. The parent with the “positive” result is the liable (paying) parent. The paying parent’s final percentage is multiplied by the expenditure amount to produce the child support amount. The child support amounts are calculated on a per child basis to account for different ages of the child (thus different costs) and/or different parenting time arrangements. These amounts are added together to produce a final monthly child support amount.

US: Vermont

Income Shares

Basic income shares model.

US: Wisconsin

Fixed percentage of income.

Modification: Wisconsin uses six formulas that vary depending on the characteristics of the case. The original percentage standard is used in most straightforward cases. However, other formulas are required for shared, split, serial (more than one child support case) and low and high-income situations. All have percentages that are variations of the percentage standard.

US: Illinois

Income Shares

Basic income shares model.

US: Delaware

Melson Formula. Two step formula that uses an incomes shares model and a percentage of income model (the latter only if there is “excess” income).

First step: Parents’ proportions of their combined incomes are used to generate their share of meeting the basic needs of children.
Second step: Consists of sharing the remaining available income of the parents with the children (after parents’ and children’s basic needs are met) and using percentages of income (percentages vary with number of children) to determine each parent’s proportion of their excess income to share with the children. This is called a Standard of Living Adjustment.

Sweden

Income Shares

Basic income shares model.

Norway

Income Shares

Basic income shares model.

France

Fixed percentage of Income

Basic fixed percentage of income model.

## Footnotes

77 Jane Venohr, Economic Basis of Updated Child Support Tables for Vermont, prepared for: Office of Child Support, Department for Children and Families, Vermont Agency of Human Services, 2015, 8.

78 Details on this section are displayed in Table 4, by jurisdiction.

79 Jane Venohr, Differences in State Child Support Guidelines Amounts: Guidelines Models, Economic Basis, and Other Issues, Journal of the American Academy of Matrimonial Lawyers, Vol. 29, 2017, 386, http://old.aaml.org/library/journal-of-the-american-academy-of-matrimonial-lawyers/volume-29-2017-number-2.

80 Diane Galarneau, Family income after separation, Statistics Canada. Income Analytic Report 0835-5525, No. 5, 1997.

81 Anne Skevik, Family Policies in Norway: Third report for the project “Welfare Policy and Employment in the Context of Family Change”, drafted for the meeting 5-6 June 2003 in Reykjavik, Iceland, revised July 2003.

82 United Kingdom, Australia, New Zealand, France, Illinois, Vermont and Wisconsin.

83 It is important to note that although the relevant national organizations collate the data annually, the percentages (if using a fixed percentage model) and the amounts (if using an income shares model) are not updated annually.

84 The parents’ basic needs are met first by subtracting a self-support reserve from their incomes.

85 Note: The tables in legislation may display only percentages, while the tables provided online will have actual amounts, i.e. the percentage calculations have been completed for the online version for ease of use.

86 Sweden and Norway differ slightly in their access to the actual costs of the budget items. Norway items are aggregated into one total entitled “consumption”, while Sweden provides the costs of the individual items.

87 More detailed discussion of “self-support allowances or reserves” can be found in Chapter V. Basically, these reserves represent an amount that will meet the basic needs of a single person. A number of jurisdictions use them as a deduction from income.

88 France, United Kingdom, Delaware, Wisconsin, Vermont and Illinois.

89 Australia, New Zealand, the United Kingdom, Wisconsin, Delaware, Vermont and Illinois.

90 Often referred to as a flat percentage model, or percentage model.

91 Jane Venohr, “Child Support Guidelines and Guideline Reviews: State Differences and Common Issues”, Family Law Quarterly, Vol 47, No.3 (Fall 2013), 327-352.

92 Ibid, 329.

93 Australia, New Zealand, Vermont, Illinois, Norway, Sweden and Delaware. Delaware is included in this list because of its similarity to the income shares model: it uses both parents’ income for determining child support amounts.

94 Jane Venohr, Child Support Guidelines and Guideline Reviews.

95 United Kingdom, Wisconsin and France.

96 The websites of the three jurisdictions describe the method underpinning their models as using a percentage income method for calculating child support.

97 Marie Cancian and Molly A. Costanzo. Comparing Income-Shares and Percentage-of-Income Child Support Guidelines. Institute for Research on Poverty, University of Wisconsin-Madison. 2017.

98 See Chapter V for additional information on how the expenditures are shared in various parenting time/custody situations.