The 1996 volume of the Utah Statistics of Income series summarizes and analyzes tax return data
available from the Internal Revenue Service (IRS) through the federal-state exchange program. The
data are based on those federal income tax returns which list a Utah address and were processed by
the IRS as of late August 1997.
Two different data tapes are available from the IRS. The first, called the master file, contains very basic information from the 1040 form, such as federal taxes, adjusted gross income (AGI), deductions and the number of exemptions claimed. The second source contains most of the individual tax form lines, such as detail on deductions and sources of income. The detailed source is not updated to reflect amendments and is not as thoroughly edited for errors as the first source. Thus, the data are not 100 percent correct, but in most cases are reliable for general orders of magnitude and averages. Since the two sources are not at the same phase in processing when the state tapes are made, totals from the two sources are generally not identical, although usually very close. Either differences in IRS processing speed or the timeliness of taxpayers in filing returns will cause discrepancies. This may result in slight differences on some tables in items such as AGI, deductions, or the number of taxpayers..
The IRS's tax data always contain information from prior-year returns that are filed late. We
generally include prior-year returns since their omission would result in a serious under-reporting of
the various income and tax magnitudes. In a sense, 1996 prior-year (1995) data is a proxy for returns
for 1996 that will be filed late. Prior-year returns are included as a separate "county" in the county
tables and are not included in either the city or ZIP Code data, since we believe the inclusion of the
data at the state level is reliable, but that its allocation to lower level geographic units is questionable.
In addition to state, county, city, and ZIP Code data on adjusted gross income, federal taxes,
exemptions, and returns by income level, this volume reports statewide data on itemized deductions,
adjustments to income, sources of income, and other important magnitudes from federal tax schedules
C through F. We have added a page on median income by city for the first time this year, as well as
a page on farmers' income from non-farm sources.
We are subject to the way taxpayers fill out their forms as far as addresses are concerned. If they use
a wrong ZIP Code, we are forced to live with it. Probably the most important error of this type is
in the "city" taxpayers claim. Some residents of the smaller communities, for example, may list Salt
Lake City as a city rather than Sandy, or Murray, for example. This also happens for residents of
unincorporated areas. Some taxpayers will also use their professional address or post office box
rather than their actual residence.
To understand what is included in "federal taxes", the reader should consult a form 1040. This
figure is what is reported on the total tax line, but self-employment taxes are not included,
while alternative minimum taxes are included as well as some other small items. Credits have
been subtracted, except the earned income tax, which is considered a payment by the IRS.
In addition, average values are only averages for taxpayers using a particular form or line. For example, for taxpayers with incomes between $40,000 and $45,000, total contributions divided by the number of taxpayers who itemize is $2,735; but our table reports a higher $2,995 which is the average for those actually making contributions.
Summary state data is reported in two places. In the section of state data in section 2, we report data
for all taxpayers, including part-year and non-residents. This data can give a distorted picture since
it includes all the income put only part of the taxes of other than full-year residents. In section 6, at
the back, we have similar tables for the state and counties that only includes full-year residents. In
the past year, we have produced a more detailed volume focusing on data from the state return.
HOUSEHOLD OR FAMILY DATA
The data as we receive it from the IRS and state returns is based on returns, but some analysts prefer
to think of households income and taxes. We have been publishing for several years our attempt to
group returns into households, generally putting children with their parents. Our methods are far
from foolproof and are detailed in our annual Family Based Statistics of Income. We have included
one summary page in the state section of this volume. It looks identical to the regular pages, but it
bears the title "household" income in the title line.
Some of the data in this report, as well as data from a growing selection of other Tax Commission
reports can be accessed on the Internet using: