Coding Issues in the ANES Cumulative File

I have, on occasion, used American National Election Studies (ANES) cumulative file to do over time comparisons. Roughly half of those times, I have found patterns that don’t make much sense. Only a small fraction of the times when the patterns didn’t make sense have I chosen to investigate the data more closely as a likely explanation for aberrant patterns. The following ‘finding’ is a result of such effort.

ANES cumulative file (1948–2004) carries a variety of indices. In creating some of the indices, it appears pre-election measures have been combined with post-election measures in some of the years. If that wasn’t enough, at least one of the times, the same index in some years has pre-election measure combined with the post-election measure, while using only post measures in other years. Here’s an example –

‘External Efficacy Index’ (VCF0648) is built out of two items –

http://www.electionstudies.org/studypages/cdf/anes_cdf_var.txt

Item 1: Public officials don’t care much what people like me think.

Item 2: People like me don’t have any say about what the government does

Item 2 is asked both pre and post-election in some cycles. In 1996, efficacy was built from

960568 (pre), 961244 (post)

http://www.electionstudies.org/studypages/1996prepost/nes1996var.txt

[you can ID post-election wave questions through the following coding category – Inap, no Post IW]. Post version of 960568 is 961245

While in 2000 it is built out of – 001527 (post), 001528 (post)

http://www.electionstudies.org/studypages/2000prepost/anes2000prepost_var.txt

I have alerted the ANES staff, and it is likely that the new iteration of the cumulative file will fix this particular issue.