Round 12 of the NLSY79 survey incorporated a large-scale experiment involving comparison between PAPI (Paper and Pencil Interviewing) and CAPI (Computer-Assisted Personal Interviewing) methods of interviewing, in anticipation of a possible conversion to CAPI-only data collection in the future. An experimental control-group design was implemented during the fielding period for the 1990 survey, allowing the examination of possible mode effects, any differences in data quality between modes, as well as differences in time and cost factors of administration. The CAPI version of the instrument was designed to replicate the paper instrument, which reduced the efficiency of the CAPI instrument somewhat. More detailed information on the results of examinations of mode effects are available through the Center. There are no indications that data quality was adversely affected by the experimental CAPI administration; indeed, the efficiency of data collection and data quality appear to have improved. Variables depicting interview modes in the 1990 data reflect respondents' assignments to various design groups at the outset of the survey as well as the mode actually used, allowing researchers to conduct their own methodologically-oriented examinations (see vars. R34003., R34004.).