Table 2.

P3P intervention customization by the patient’s personal profile

Patient Query Component	Internal Algorithm	Intervention Delivered to Patient
Prostate cancer information priorities:	Patient was presented 36 paired comparisons of 9 information topics and selected from each pair the topic of greater priority to him to receive information The top 4 most highly prioritized were calculated.	Information relevant to the top 4 priorities was briefly summarized on-screen. At the end of the intervention, the patient received printed teaching sheets on each topic.
Stage of disease Prognosis Treatment options Side effects Home self-care Impact on family Sexuality Social activities Family risk
Demographics:	Patients’ ages were categorized as under 60 or 60+ years of age. Patients self-identified as white, black, or other (Asian, Native American).	Videos featured a patient actor close to the patient in age and matched for race as below; those reporting “other” or skipping the race item were offered intervention content tailored to white patients.
Date of birth Self-reported race
Preferred role in the Treatment decision (Control Preferences Scale)	Patient selected response option: 1 or 2 (active role) 3 (shared role). 4 or 5 (passive role) The preferred role was highlighted in the intervention text and video, (Multimedia Appendix 2).	Text and video coaching customized to patient’s race was offered for a patient to express his preferred role. In the video, the doctor acknowledged the patient’s preference (Multimedia Appendix 3). The patient was offered the opportunity to view the text and video for other control preferences.
Influential People:	Patient selected option for how much influence these people had as he considered his treatment choices: (1) no influence (2) a little influence (3) some influence (4) a lot of influence. For each reported to have “some influence” or “a lot of influence,” the intervention offered text and a video coaching the patient to tell his doctor.	Text and video coaching were offered for the patient to express who were the influential people in his decision process. The doctor in the video acknowledged the importance of these influential people and helped the patient compare his own views and situation to those of influential people (Multimedia Appendix 4). At the end of the intervention, the patient printed the teaching information with “fill in the blank” text he could use to prepare for the exam visit.
coworkers friends outside work spouse/partner other family members
Influential outcomes:	For each of these treatment outcomes, the patient selected how much importance or influence it had on his decision: (1) no influence (2) a little influence (3) some influence (4) a lot of influence. The outcome rated most influential was used as the example for teaching about statistics. In the case of a tie between outcomes, the example was selected randomly from those rated most highly influential. For the outcomes rated “some influence” or “a lot of influence,” the patient was offered text and video coaching.	Text and a graphic illustration taught numeracy skills useful to understanding statistics about possible outcomes. The example provided was highly salient to the patient (Multimedia Appendix 5). Text and video coaching customized to age was offered for the patient to express the influential factors in his decision process. The doctor in the video acknowledged the importance and helped the patient understand the relative likelihood of each treatment option’s impact on these factors (Multimedia Appendix 6). At the end of the intervention, the patient printed the teaching information with “fill in the blank” text he could use to prepare for the exam visit.
survival bladder function bowel function sexual function
Current symptoms: (EPIC questionnaire)	Each symptom domain included an overall impact item. For each item where the patient responded that the symptom is a “moderate problem” or a “big problem,” the symptom was listed on the intervention menu page to learn more about (Multimedia Appendix 7).	Text and video coaching customized to race was offered on each symptom the patient experiences as a problem. In the video, the patient reported his symptom and the doctor offered to help him understand how different treatments might impact his symptoms differently (Multimedia Appendix 8). At end of the intervention, the patient printed the teaching information with “fill in the blank” text he could use to prepare for the exam visit.
urinary bowel sexual
Useful links	Not customized–the same content was offered to all patients.	Links to 4 highly rated professional websites offering general information about prostate cancer.