The manual says "If you are using electronic data files, you may find a figure labeled "Analysts' Estimate" at the bottom of the [preferred procedure] dialog box. This figure is calculated using the "Analysts' EPS Growth Rate Estimate" to compound their estimate of the current fiscal year's earnings for four more years. (Pg 117 in the Toolkit version 5 manual; Pg 137 in the Toolkit version 4 manual.)
When using the BetterInvesting S&P Stock Data Service data files (formerly knows as "OPS"), Toolkit does not calculate the figure itself. It obtains it from field 109 of the OPS data file (field 347 contains the same value, but Toolkit uses field 109). The value in fields 109 and 347 comes precalculated from S&P (thanks to James Rubinstein for this information).
Using the "Analysts' EPS Growth Rate Estimate" (field 229) to compound the current FY EPS estimate (field 364) does not always produce the exact value in field 109. The rounding of OPS data fields vs. the raw data provided by S&P may account for this (field 109 is rounded to 3 decimal places and fields 229 and 364 are probably rounded too).