A corollary of the proposition that taxes should weigh similarly on persons similarly situated is the notion that when persons are not similarly situated their tax liabilities should differ. To accomplish this, income tax statutes usually provide for (1) individual allowances or exemptions, which differentiate between large and small family units, and (2) deductions that give preferential treatment to taxpayers reporting expenditures that are thought to justify some lightening of their burden.
There are several ways of allowing for differences in family units. One is to give an exemption for each dependent, either on a flat per capita basis or in accordance with a schedule. When income is taxed at graduated rates, exemptions are worth more to high-income than to low-income families. In order to provide equal tax allowances for dependents to families of the same size at different income levels, each exemption can be multiplied by the standard or basic rate of tax and so be converted into a uniform tax credit that is subtracted from liability. Inflation erodes the real value of tax allowances specified in nominal or monetary terms (dollars, euros, etc.). Historically, this problem has been addressed by periodically adjusting such amounts to higher levels. More recently there has been a trend toward âindexingâ amounts such as personal exemptions, standard deductions, and bracket limits in the rate structure by linking them to a price index that measures the degree of inflation. Indexing, which need not involve an increase in complexity, increases the equity of the tax system, but it reduces the taxâs countercyclical influence.
The number of dependents is not the only way that families may differ in taxpaying capacity. In some families only one spouse earns income, whereas in others both the husband and wife may work. If, in a family of the latter type, husband and wife are allowed to file separate returns, their combined tax liabilities under a progressive income tax may be less than those of a family similarly situated but with a single income earner. The two families will pay the same tax if husband and wife are required to file a joint return in which their earnings are pooled; however, the working couple may be taxed at a higher rate than two single people with the same income. The issue between joint and separate returns is further complicated by the fact that if separate returns are permitted and are subject to the same rate structure as joint returns, families with investment income can reduce their tax liabilities by splitting up their holdings. Depending on how this problem is solved, there may be either a penalty or a tax bonus for marriage.
Various ways of dealing with this problem have been adopted in different countries. In the United States full income splitting has been allowed since 1948, when married taxpayers were given the option of filing joint returns using a rate schedule with brackets twice as wide as those in the schedule for married persons electing to file separate returns; i.e., the tax on joint returns is twice the tax that would be imposed if there was only one income receiver and that personâs income was half as large as the joint income. This meant that the tax rate for joint returns did not rise as sharply as that for separate returns, so a single person was likely to pay more than a married person with the same adjusted gross income but filing a joint return. In 1969 the disadvantage experienced by single persons was reduced by the provision of a completely separate rate schedule for them, which created a âmarriage penaltyâ that taxed married couples at a relatively higher rate. In France the family is the taxable entity; there is only one rate schedule, but relief for family commitments is achieved by what is known as the family-quotient system. This is a form of income splitting in which the single graduated rate schedule is applied to a figure arrived at by dividing total family income by the number of âunitsâ represented, with each child counting as half a unit. The tax, as so determined on a fraction of the familyâs income, is then multiplied by the number of family âunitsâ to arrive at the familyâs tax liability. In Germany husband and wife are assessed jointly, but income splitting is allowed in the same way that it is in the United States. Sweden also has a dual rate structure, but in that country the difference between the rates applicable to married couples and to single persons varies with the level of income; in the middle income brackets couples are more heavily taxed, and in the high brackets burdens are much the same for married and single taxpayers. Finally, in a number of countries, including India, Japan, Argentina, and Israel, only separate returns are allowed.
