This study investigates the mental model comparison between expert and novice performance improvement practitioners. Nonexperimental survey research design was applied. Based on specific criteria, 11 critical concepts out of 30 were selected by 23 experts. Sixteen of those 23 experts provided data about the relatedness of 55 concept‐pairs generated from the 11 concepts to develop the common mental model of experts in the Knowledge Network Organizing Tool utilizing Pathfinder scaling. Two‐hundred‐forty‐two practitioners participated in the further phases of the study. Out of those practitioners, 33 novices, who have not met any of the criteria used for expert selection, are selected. Those novices also provide similar data for the common mental model of novices. The results of the study show that the expert model has more consistent and hierarchical structure than the novice model. Discussions and further research recommendations are provided.