Iterative Proportional Fitting for a Two-Dimensional Table
An informal description of two-dimensional IPF that I prepared for my coworkers and fellow researchers. Please feel free to offer comments or corrections. IPF is a big name for a pretty simple (but terrific) technique-- it is used quite a bit, but I think it could be used more. Nels Tomlinson handed down much of any knowledge and computer code that I have on IPF.

Iterative Proportional Fitting for a Three-Dimensional Table
A description of three-dimensional IPF.

Iterative Proportional Fitting for a Four-Dimensional Table
A description of four-dimensional IPF.

Alaska Department of Labor's Iterative Proportional Fitting R Code
R code that I use for two-, three- and four-dimensional IPF. If you use, share or reproduce any files in the linked "IPF.zip" file, do acknowledge their source: Alaska Department of Labor and Workforce Development, 2009. This code has been used in a number of projects, including this research on computer and Internet use at U.S. public libraries, this work on employment flows in the U.S., and this guide for creating small-area cross tabulations. Though I (Eddie Hunsinger) did pieces of the development of the IPF functions, the heavy lifting (the bulk of the 2D and 3D functions) was done by Nels Tomlinson, my predecessor at the Alaska Department of Labor. The Alaska Department of Labor and Workforce Development and its employees (past, present and future) are not responsible for any problems associated with use of the files in the "IPF.zip" file. There is no warranty for the files in the "IPF.zip" file.

Webb Sprague's Iterative Proportional Fitting SAS Code
A great SAS macro for two-dimensional iterative proportional fitting, developed by Webb Sprague, a demographer with the State of Washington's Office of Financial Management. Please note this code was developed recently (August 2011), and has only been tested with some sample data.

A Very Particular IPF Application
Use of IPF to reasonably fit sampled "Group Quarters" (GQ) (shared living facilities, as opposed to traditional households) data to separately-estimated GQ-type (e.g. prisons, dorms, etc.), GQ-county (location) and GQ-age (age of resident) control/marginal totals, given sparse and tightly-clustered sample-cell-data by type and county.

Iterative Proportional Fitting Links
Links to some IPF papers that I've found useful.

Alaska Research