BACKGROUND: The Pediatric Laparoscopic Surgery (PLS) simulator is the only validated tool for pediatric Minimal Access Surgery. Construct validity (the ability to discriminate between novice, intermediate and expert) for the PLS simulator had previously been established on the basis of the total PLS score, as well as the individual performance on three of the five tasks. We describe the process and methods used to establish independent construct validity for a fourth task: pattern-cutting. METHODS: After considering various options for the possible modifications of the task itself, we retrospectively altered the way the pattern-cutting task was scored by modifying the weighting of precision versus time without changing the task itself. This was subsequently tested prospectively at the 2011 Canadian Association of Pediatric Surgeons meeting. RESULTS: Modification in the scoring metrics allowed differentiation within a previously tested cohort of 84 candidates (20 novices: score=48 ± 16, 19 intermediates: score=59 ± 18, 45 experts: score=69 ± 12 p=0.01). This was validated prospectively in a cohort of 18 experts and 7 intermediates (65 ± 8, 54 ± 17 p=0.03). CONCLUSIONS: Construct validity for the pattern-cutting task was established by modification of the scoring metrics. This was validated both retrospectively and prospectively.
BACKGROUND: The Pediatric Laparoscopic Surgery (PLS) simulator is the only validated tool for pediatric Minimal Access Surgery. Construct validity (the ability to discriminate between novice, intermediate and expert) for the PLS simulator had previously been established on the basis of the total PLS score, as well as the individual performance on three of the five tasks. We describe the process and methods used to establish independent construct validity for a fourth task: pattern-cutting. METHODS: After considering various options for the possible modifications of the task itself, we retrospectively altered the way the pattern-cutting task was scored by modifying the weighting of precision versus time without changing the task itself. This was subsequently tested prospectively at the 2011 Canadian Association of Pediatric Surgeons meeting. RESULTS: Modification in the scoring metrics allowed differentiation within a previously tested cohort of 84 candidates (20 novices: score=48 ± 16, 19 intermediates: score=59 ± 18, 45 experts: score=69 ± 12 p=0.01). This was validated prospectively in a cohort of 18 experts and 7 intermediates (65 ± 8, 54 ± 17 p=0.03). CONCLUSIONS: Construct validity for the pattern-cutting task was established by modification of the scoring metrics. This was validated both retrospectively and prospectively.