Background: Achievement of colonoscopy outcomes depends on high-quality bowel preparation by patients; yet inadequate preparation is common.

Objective: To develop and test an educational booklet to improve bowel preparation quality.

Design: "Before-and-after" study followed by randomized controlled trial.

Setting: Veteran Affairs medical center.

Patients: Patients undergoing outpatient colonoscopy

Measurements: The investigators first performed cognitive interviews to identify knowledge and belief barriers to high-quality colonoscopy preparation. The investigators then created a patient educational booklet addressing patient barriers to improve preparatory behaviors. The investigators tested the booklet in 2 sequential studies: (1) controlled "before-and-after" study in patients undergoing colonoscopy during 2 consecutive months: 1 without and 1 with the booklet; (2) randomized controlled trial. The outcome in both studies was bowel preparation quality measured on a 6-point Likert scale (>5="good"). In each study the investigators compared the proportion achieving a "good" preparation between groups and performed logistic regression to measure the effect of the booklet on preparation quality while adjusting for the purgative received.

Limitations: Unknown impact on polyp yield and cancer reduction.

Inclusion Criteria:

• Any patient scheduled to undergo outpatient colonoscopic CRC screening or surveillance in VAGLA

Exclusion Criteria:

• In patient admissions