In two independent studies of questionnaire administration, respondents completed multidimensional self-concept inventories within four randomized research conditions that mirrored the most common administration formats used in practice: paper booklets with and without answer sheets and computer questionnaires with single versus multiple items per screen. Strong differences among conditions emerged for completion time, but not for psychometric properties of scores (means, variances, reliability coefficients, concurrent validity coefficients). Answer sheets increased completion time by 24% to 34%, single-item displays by 20% to 25%, and computerization by 13% to 17%. Completion time was longer for multiple-alternative than for rating-scale items, but relative effects of answer sheets, single-item displays, and computerization remained consistent. We discuss implications for questionnaire construction and administration.