This study aimed to investigate the item "Response Time Fidelity scores" ("RTFs"), "KuderRichardson Reliability" ("KR[subscript 20]") and "Cronbach's Alpha Reliability" ("alpha") coefficients, calculate "KR[subscript 20]" coefficients with "RTFs" for 30 threshold points between 1 and 30 seconds and compare these values on plots, estimate the threshold point in the literature to support these plots and conduct risk analyses with "Cox Proportional Hazards Model" ("Cox-HM") on the initial data and the new data determined by the threshold value. This study is a descriptive research. The participants were pre-service science teachers at a state university in Turkey (n:115). The study was conducted in two groups. In Group-1 (n:57), a "Three-Tier Diagnostic Test" ("[subscript 3]TDT") was performed, and in Group-2 (n:58), a "Multiple-Choice Test" ("MCT") was applied. Tests consisted of 63 items and chemical concepts. As a result, it was found that item response times could be used in the validity and reliability studies of measurement tools. Moreover, examinees spent less time and effort in Tier-II of "[subscript 3]TDT." In future research, response times and RTFs may have roles in development of "[subscript 3]TDTs" about different concepts. Moreover, these may be used in Rasch and Parametric Logistic Analysis for "[subscript 3]TDT." This study may be repeated using different psychometric scales.