Information With or Without Numbers For Optimizing Reasoning About Medical Decisions

Completion of colonoscopy, fecal immunochemical testing (FIT), or other CRC screening test within 6 months of enrollment, based on documentation in the participants' electronic health record. If a patient completed both screening tests and the colonoscopy was a follow-up to a positive FIT, they were considered having completed a FIT only. If the FIT was negative and the patient still had a colonoscopy, they were considered to have completed both tests.

Multiple choice question assessing subject's intention in getting a CRC screening test in the next 6 months. The response options were: 5=Definitely, 4=Probably, 3=May or may not, 2=Probably not, and 1=Definitely not. Higher positive change means CRC screening intention increased. Increased intention to be screened is a better outcome.

Multiple choice questions assessing subject's perception of how likely they are to get colon cancer in the next 5 years, in the next 10 years, and sometime during their lifetime. Each had response options: 4=very likely, 3=somewhat likely, 2=somewhat unlikely, and 1=very unlikely. The mean of the 3 questions was calculated (each combined score has a range of 1 to 4) at baseline and post-intervention and then change from baseline was calculated using the mean at post-intervention minus the mean at baseline. The range for change could be from -3 to 3 with higher values meaning an increase in perceived risk which is a better outcome.

Assessed separately for colonoscopy (4 questions) and FIT (4 questions), using items drawn from validated scales for measuring benefits and self-efficacy of colonoscopy and FIT. All items had Likert-type response options where 5=strongly agree to 1=strongly disagree. Mean values were calculated within each set of questions (each combined score has a range of 1 to 5) at baseline and post-intervention and then change from baseline was calculated using the mean at post-intervention minus the mean at baseline. The range for change could be -4 to 4 with higher values meaning perceived benefits increased which is a better outcome.

Assessed separately for colonoscopy (11 questions) and FIT (9 questions), using items drawn from validated scales for measuring barriers and self-efficacy of colonoscopy and FIT. All items had Likert-type response options where 5=strongly agree to 1=strongly disagree. Mean values were calculated within each set of questions (each combined score has a range of 1 to 5) at baseline and post-intervention and then change from baseline was calculated using the mean at post-intervention minus the mean at baseline. The range for change could be -4 to 4 with lower values meaning perceived barriers decreased which is a better outcome.

Qualitative knowledge is assessed with five multiple choice and five true/false questions regarding general information (including risk factors, screening test options, and test frequency) of CRC and CRC screening. Knowledge scores were derived by summing correct responses to the 10 individual knowledge questions (range, 0-10), and change from baseline was calculated using the knowledge score at post-intervention minus the knowledge score at baseline. The range for change could be 0 to 10 with higher values meaning an increase in knowledge which is a better outcome.

Decision conflict is assessed using the16-item Decision Conflict Scale. Scores will range from 0 (low decision conflict) to 100 (high decision conflict). Negative change means decision conflict decreased. A decrease in decision conflict is a better outcome.

Subjective numeracy was determined using the Subjective Numeracy Scale (SNS), a validated instrument that involves 8 Likert-type questions regarding the participant's preference for or dislike of numeric information and their perception of their ability to understand it. Each item has a six-point response option from 1-6. The higher the number, the higher the subjective numeracy. All participants were divided into two groups: above (high numeracy) and below (low numeracy) the median for their total subjective numeracy score.