SOI Tax Stats - Gift Tax Study Data Sources and Limitations


This page contains information about data sources and limitations for SOI's Gift tax study.

Please visit Gift Tax Statistics to access articles and tables from the study.

The sample design for the Gift tax study is a stratified probability sample with two stratifying variables: taxability status and size of total gifts (prior to the subtraction of annual exclusions and deductions in the calculation of total taxable gifts). Taxability status is divided into two categories: nontaxable (i.e., no gift tax liability reported) and taxable (i.e., gift tax liability reported). The second stratifier, size of total gifts, is divided into four or five categories, depending on taxability status. Each stratum is labeled with a sample code.

Each return in the sample is weighted to reflect its share of the population of returns filed in the year of interest. Because of the variation of the sample sizes, post-stratification is used. The post-stratified weight is computed by dividing the realized population count of filed returns in a given stratum by the realized number of sample returns in that stratum. These weights are adjusted for missing returns, rejected returns, and outliers. These weights are applied to the sample data to produce aggregate estimates for items of interest, such as total gifts and total taxes.