Table 5.
Internal consistency and inter‐item correlations by dimension including sensitivity analysis with specific populations.
| Cronbach's Alpha Coefficient | Inter‐item correlation | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Dimensions and individual items within each dimension | Item Numbers | All | Drug | Disease | African American | All | Drug | Disease | African American |
| All items | 1–44 | .96 | .93 | .93 | .92 | .33 | .28 | .29 | .25 |
| Informed consent | 1–13 | .86 | .87 | .86 | .84 | .32 | .33 | .33 | .28 |
| 1. Overall study explained understandably 2. Someone took the time to answer questions about the study 3. Study details explained understandably 4. Risks/benefits of joining study explained 5. Study details included in informed consent docs 6. Informed consent document understandable 7. Prepared for what to expect by informed consent document 8. Something happened that you were not prepared for 9. Prepared by info/discussions before participation 10. Felt pressure from research staff to join study 11. Had enough time before signing informed consent 12. Felt pressure from research team to stay in study 13. Understood which tests/visits were for research* | 1–12 | .84 | .85 | .85 | .83 | .31 | .32 | .33 | .29 |
| Coordination of care | 14–20 | .69 | .69 | .70 | .71 | .24 | .24 | .25 | .26 |
| 14. Research team ready on time for visit 15. Had to wait too long for visit/procedures to begin 16. Had to wait too long between procedures/tests 17. Knew how to reach research team 18. Able to reach member of research team when needed 19. One person organized in involvement in study 20. Research staff gave conflicting information* | 14–19 | .72 | .71 | .72 | .74 | .30 | .29 | .30 | .32 |
| Information, education and communication | 21–28 | .80 | .81 | .81 | .76 | .33 | .34 | .35 | .29 |
| 21. Coordinator/nurse answered questions‐understandably 22. Investigator/doctor answered questions‐understandably 23. Pain/discomfort explained during informed consent 24. Experienced unexpected pain/discomfort 25. Risks/benefits included in informed consent 26. Easy to get answers from research team 27. Reasons for delays explained* 28. Summary of results written understandably* | 21–26 | .71 | .72 | .71 | .68 | .29 | .30 | .29 | .27 |
| Respect for participant preferences | 29–36 | .83 | .85 | .82 | .72 | .37 | .42 | .36 | .25 |
| 29. Had enough physical privacy while in study 30. Personal/research information protected while in study 31. Met with investigator/doctor as much as wanted 32. Felt like a valued partner in research process 33. Staff provided assistance for language‐differences* 34. Wanted to receive results of routine tests* 35. Research staff respected my cultural background* 36. Staff respected language differences* | 29–32 | .66 | .67 | .67 | .66 | .33 | .33 | .34 | .32 |
| Trust | 37–44 | .85 | .85 | .85 | .84 | .42 | .41 | .42 | .40 |
| 37. Confidence and trust in nurses/coordinator 38. Confidence and trust in investigators 39. Coordinator/nurse listened carefully 40. Investigator/doctor listened carefully 41. Investigator/doctor treated with courtesy and respect 42. Coordinator/nurse treated with courtesy and respect 43. Coordinator/nurse discussed anxieties/fears* 44. Investigator/doctor discussed anxieties/fears* | 37–42 | .83 | .81 | .83 | .85 | .46 | .41 | .44 | .49 |
Items represent shortened paraphrased summaries of the questions and not the wording used in the questionnaire.
Items are listed in each dimension using short forms of the questions. The items included in dimensions are separate actionable questions. Cronbach's Alpha and Inter‐item correlation coefficients are calculated for the entire response set (All) of all items (All), and also analyzed for each dimension as a whole (All), and also in sensitivity analyses using only individuals in studies involving an investigational drug or procedure (Drug), or participants who had to be disease‐affected to enrol (Disease), or participants who self‐identified as African‐American (African American). For each dimension, there are two sets of coefficients for all the analyses. The upper set of coefficients represents the analysis including all the questions and responses within the dimension. Only those respondents who completed all questions are included in the analysis. The lower set of coefficients includes at least 50% of respondents by removing questions with high percentages of not applicable responses. The shaded items are questions eliminated from the calculations in the list‐wise deletion analysis due to a large number of ‘not applicable’ responses.
*items removed so that more than 50% of research participants were included in analysis.