Iterative Proportional Fitting? That old chestnut? Haven’t people been banging on about that for hundreds of years?! Well, about 70, but I guess some of the old ones are the best ones… (Deming and Stephan for all those pub quiz fans out there!)
Anyway, I recently stumbled across IPF again in the way that people who work with data matrices do from time to time. I also realised that there’s not a whole lot of useful generic programmes out there for you to carry out this pretty useful procedure, and like a total nit, I’ve been doing it the hard way for a long time. Therefore I have spent the last day or so writing a nice little bit of VBA (arrghh, not Microsoft?! Yes! And it even runs in the much maligned but fantastic Excel). The program will take in data in either matrix or paired list format and will run IPF to update the interior cell values to a new set of column and row margins whilst maintaining the original ratio structure of the table.
I think Paul Norman produced a similar program in Excel a few years ago, but if you can find it anywhere on the web you’re a better Googler than me! Hopefully this programme improves Paul’s a little with the flexibility for matrices and paired lists and with it taking advantage of the increased number of columns available in the latest versions of Excel. Also, this will be freely available to download from here from now on. If you’d like to use the program, it can be downloaded from the link below:
Oh and here’s a nice picture that my ENFOLD-ing colleagues will enjoy! 🙂