In the case of multiple test applications, the equation of the grades students get from different test types is highly significant. Thus, test equating is applied usually during which anchor items are used. However, there are certain problems in that students might remember the anchor items, tests might not include anchor items and/or anchor items are not used in the practice tests. In this case, alternative techniques are required in order to achieve reliable test equating. One of these methods is common subject equating. Nevertheless, the literature does not include much research on the efficiency of common subject equating under various conditions such as test lenght, sample size, ability distribution, item types, ability estimation method and Item Response Theory models. In this sense, this study aims at comparing the common subject equating methods in terms of sample size, test lenght and ability distribution. The study was carried out on simulated data. Simulation conditions were identified so that the sample size (250 and 1000), test lenght (20 and 40) and ability distribution is similar and different. Sample size was depicted so that all subjects were common and/or %20 of the subjects were common. Data was generated using WINGEN, ability parameters were estimated through PARSCALE and test equating was conducted using MS EXCEL. The simulation conditions study of the research is in progress and the findings will be released in the future.