Table 3

Principal component analysis (PCA) with varimax rotation: final two-component solution and Cronbach's α of each component

PCA factor loadings
Recall items (n=17): closed-ended and multiple choice response formats (Cronbach's α=0.79)
 Told I can freely take part0.719
 Told I can withdraw anytime0.314
 Will know the study drug/vaccine0.552
 Unauthorised person will not know about my participation0.372
 Told the contact person0.540
 My participation can be stopped without my consent0.420
 Will I be paid for taking part0.395
 How were participants divided into groups0.403
 At what point can I leave the study0.371
 Meaning of signing/thumb-printing consent form0.390
 How I decided to take part0.429
 What will I receive as compensation0.520
 What will happen if I decide to withdraw0.464
 Reason for doing the parent study0.393
 Which are the study procedures0.489
 Which are the study activities0.617
 Which are the main benefits of taking part0.390
Understanding items: open-ended response format (n=9; Cronbach's α=0.73)
 Describe the function of the study drug/vaccine0.647
 Mention the name of the contact person0.451
 Tell what researchers want to find in this study0.312
 Number of study visits0.492
 Tell what were done during the study visits0.498
 Describe how participants were divided0.689
 Tell the difference between taking part in a study and going to hospital0.464
 What are the possible unwanted effects of a study drug/vaccine0.388
 Why were participants given different drugs/vaccines0.437