This page contains information about data sources and limitations for SOI's annual Partnership Study. The “Tax Year” statistics in the annual SOI Bulletin article are estimates based on a stratified probability sample of Forms 1065 which a population of partnerships filed with the IRS. A specific tax year (e.g., tax year 2021) covers returns the IRS processed during the year the returns were due (e.g., calendar year 2022). All partnerships engaged in business in, or having income from sources within, the United States were required to file a Form 1065, U.S. Partnership Return of Income, to report income or loss, deductions, tax credits, and other tax-related items the partnership generated during a specific accounting period. The statistics are only for active partnerships, which are defined as those reporting any items of income or deduction derived from a trade or business, or from rental or portfolio income. The population was stratified into classes based on industry, type of return, size of total assets, and size of certain receipt or income amounts from both ordinary business income (loss) and portfolio income (loss). Returns were selected from these classes at various probabilities ranging from 0.07 percent to 100 percent and were weighted to represent the total population. There are sampled returns that were ruled “out of scope” because they had no activity or duplicated other returns already in the study. This resulted in a final sample, which was slightly smaller than the original set of returns, and an estimated overall active population slightly less than the original target population. Because the data presented in this article are based on a sample of returns, they are subject to sampling error. To properly use the data, the magnitude of the potential sampling error needs to be known. Coefficients of variation (CVs), the ratio of an estimate's standard error to the estimate, are used to measure this magnitude. The estimate is judged more reliable when the coefficient of variation is smaller. A section in the annual SOI Bulletin article, “Data Sources and Limitations,” presents the coefficients of variation for certain money amounts and selected industrial sectors. Find Partnership SOI Bulletin articles for more information.
