Validation of the second-generation Olympus colonoscopy simulator for skills assessment.
OBJECTIVE
Simulators have potential value in providing objective evidence of technical skill for procedures within medicine. The aim of this study was to determine face and construct validity for the Olympus colonoscopy simulator and to establish which assessment measures map to clinical benchmarks of expertise.


METHODS
Thirty-four participants were recruited: 10 novices with no prior colonoscopy experience, 13 intermediate (trainee) endoscopists with fewer than 1000 previous colonoscopies, and 11 experienced endoscopists with more than 1000 previous colonoscopies. All participants completed three standardized cases on the simulator and experts gave feedback regarding the realism of the simulator. Forty metrics recorded automatically by the simulator were analyzed for their ability to distinguish between the groups.


RESULTS
The simulator discriminated participants by experience level for 22 different parameters. Completion rates were lower for novices than for trainees and experts (37 % vs. 79 % and 88 % respectively, P < 0.001) and both novices and trainees took significantly longer to reach all major landmarks than the experts. Several technical aspects of competency were discriminatory; pushing with an embedded tip ( P = 0.03), correct use of the variable stiffness function ( P = 0.004), number of sigmoid N-loops ( P = 0.02); size of sigmoid N-loops ( P = 0.01), and time to remove alpha loops ( P = 0.004). Out of 10, experts rated the realism of movement at 6.4, force feedback at 6.6, looping at 6.6, and loop resolution at 6.8.


CONCLUSIONS
The Olympus colonoscopy simulator has good face validity and excellent construct validity. It provides an objective assessment of colonoscopic skill on multiple measures and benchmarks have been set to allow its use as both a formative and a summative assessment tool.
Haycock
A V
AV
Wolfson Unit for Endoscopy, St. Mark's Hospital, Imperial College London, London, UK. ahaycock@imperial.ac.uk
Bassett
P
P
Bladen
J
J
Thomas-Gibson
S
S
D020685:Colonoscopes; D003113:Colonoscopy / Q000379:methods*; D003198:Computer Simulation; D003194:Computer-Assisted Instruction; D004501:Education, Medical / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013647:Task Performance and Analysis; D014584:User-Computer Interface