Analysis of analytical temperature rising elution fractionation (TREF) data involves conversion of elution temperature information to branching information via a calibration curve relating the two. The curve is generated by analysis of polymer fractions recovered using preparative TREF techniques. In preparative TREF a stepwise temperature ramp is used to recover these fractions so that samples with sharp branching distributions are obtained. A continuous temperature ramp, as in analytical TREF, produces samples that differ in branching properties from the stepwise ramp at the same temperatures. The analytical TREF data can be corrected for these differences by an iterative computer program so that a calibration curve generated by preparative techniques can be used to convert the analytical TREF data to branching distributions. Analytical TREF results should be corrected for fraction overlap before relating these data to polymer properties. © 1993 John Wiley & Sons, Inc.