The purpose of this quantitative survey study was to test the Leontief input/output theory relating the input of IT certification to the output of the English-speaking U.S. human resource professional perceived IT professional job performance. Participants (N = 104) rated their perceptions of IT certified vs. non-IT certified professionals' job performance. Presented identical, ordinal Likert-type scale questions twice, participants rated 21 previously validated IT professional Behavioral Rating Scale technical, managerial, and people factor skills: once for the IT certified professionals and once for the non-IT certified professionals. Cross-tabulations were calculated for each skill, comparing the IT-certified rating to the non-IT certified rating. Symmetric lambdas, chi-square statistics, Pearson's Rs, and Spearman's correlations were calculated, each with an observed significance of 0.000, thereby rejecting the null hypothesis that the HR professional perceived skill levels for the IT certified and non-IT certified professionals were the same. Two of the technical factor skill levels for the IT certified professionals, functional application knowledge and programming, were least likely to predict the skill levels for the non-IT certified professionals. The technical-functional application knowledge skill had a symmetric lambda of 0.30. Thirty percent of the time, the IT certified professional ratings predicted the non-IT certified professional ratings with a Pearson's R of 0.46 and a Spearman's correlation of 0.49. The technical programming skill had a symmetric lambda of 0.28. Twenty-eight percent of the time, the IT certified professional ratings predicted the non-IT certified professional ratings with a Pearson's R of 0.57 and a Spearman's correlation of 0.56. Thus, these two technical factor skills were the most likely perceived by the HR professionals as related to the IT certification. The result requires further study. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]