Tada 1997.

Methods	Generation of allocation sequence: "Randomly allocated". Allocation concealment: Not stated. Blinding: Unblinded to endoscopist. Blinded to patient. Inclusion of all randomised patients: All randomised patients were included in data analysis.
Participants	Number: 140 Age: 61.1 +/‐ 10.5 years in Group 1, 59.1 +/‐ 11.5 years in Group 2 Source: Patients attending for screening colonoscopy at First Department of Surgery, Tokyo Medical and Dental University, Japan. Inclusion criteria: All patients recommended to undergo screening colonoscopy at this unit. Exclusion criteria: No previous abdominal surgery.
Interventions	Screening colonoscopy was undertaken with an Olympus optical‐core colonoscope or an Olympus optical‐core colonoscope with a 10mm transparent plastic cap (17mm outer diameter, 2mm wall thickness and 10mm in length).
Outcomes	Included in review: Caecal intubation time, Polyp detection rate and Pain during procedure. Excluded from review: Endoscopic Mucosal resection of flat lesions vs strip biopsy.
Notes	Location: First department of Surgery, Tokyo Medical and Dental University Source of funding: Not stated Attempts to clarify information: not required Language of Publication: English
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"randomly assigned"
Allocation concealment (selection bias)	High risk	Not stated
Blinding (performance bias and detection bias) All outcomes	High risk	Single blinded (to patient not endoscopist)
Incomplete outcome data (attrition bias) All outcomes	Low risk	None
Selective reporting (reporting bias)	Unclear risk	Caecal intubation rate was not reported
Other bias	Unclear risk	Source of funding not described