The purpose of this study is to investigate whether factor scores can be used instead of ability estimation and total score. For this purpose, the relationships among total score, ability estimation, and factor scores were investigated. In the research, Turkish subtest data from the Transition from Primary to Secondary Education (TEOG) exam applied in April 2014 were used. Total scores in this study were calculated from the total number of correct answers given by individuals to each item. Ability estimations were obtained from a three-parameter logistic model chosen from among item response theory (IRT) models. The Bartlett method was used for factor score estimation. Thus, the ability estimation, sum, and factor scores of each individual were obtained. When the relationship between these variables was investigated, it was observed that there was a high-level, positive, and statistically significant relationship. In the result section of this study, as variables have a high-level relationship, it was suggested that since variables could be used interchangeably, factor scores should be used. Although the total scores of individuals were equal, there were differences in terms of factor score and ability estimations. Therefore, it was suggested that item response theory assumptions were not met, or factor scores should be used when the sample size is small.