Table 3 Mean importance ratings for individual items in surveys 1 and 2, ordered by survey 2 importance ratings (possible score range 1–9: 1 = lowest importance, 9 = highest importance)

1. Specifying intervention components

7.81

1.31

3

2. How to disseminate behavioral trial research findings to increase implementation

7.83

1.45

2

3. Methods for ensuring that behavioral interventions are implementable into practice and policy

7.75

1.52

4

4. Use of systematic approaches to move from evidence to intervention components

7.9

1.19

1

5. Selecting appropriate behavioral outcomes for trials

7.66

1.23

6

6. Tailoring interventions to specific populations and contexts

7.69

1.66

5

7. Reporting intervention and comparison group(s) intervention content

7.64

1.26

7

8. Selection of suitable comparison group(s) within trials

7.55

1.15

8

9. Development of novel research designs to test behavioral interventions as alternatives to, or to complement, standard randomized controlled trials (RCTs)

7.42

1.46

11

10. Measurement of process(es) of change or mechanisms of action within interventions

7.44

1.53

10

11. Strategies to optimize intervention fidelity (including adherence)

7.29

1.43

13

12. Using theory in behavioral intervention development

7.04

1.8

18

13. Standardizing methods for reporting behavioral trials

7.25

1.49

15

14. Determining clinically significant changes in outcomes within trials

7.27

1.38

14

15. Relationship between behavioral outcomes and clinical/other outcomes

7.45

1.42

9

16. Standardized methods for reporting and registering behavioral trials’ protocols

7.16

1.58

16

17. Methods to assess intervention fidelity

7.27

1.64

14

18. Exploring impact of mode of intervention delivery

7.36

1.33

12

19. Strategies to maximize trial participant recruitment and retention

7.05

1.75

17

20. Investigating the impact of intervention intensity on outcomes (new item in survey 2)

N/A

N/A

N/A

21. Incorporating stakeholder input in intervention development and delivery

6.91

1.48

19

22. How to optimize stakeholder engagement in behavioral trial research

6.86

1.41

21

23. Determining ideal timing of outcome measurement within trials

6.88

1.49

20

24. Novel approaches and designs for piloting behavioral interventions

6.86

1.88

21

25. Establishing criteria for progressing from trial piloting phases to full RCT

6.91

1.61

19

26. Contamination between study arms (intervention and comparison) within trials

6.84

1.57

22

27. Testing the impact of stakeholder engagement in behavioral trial research

6.70

1.74

23

28. Impact on intervention delivery of characteristics (such as qualifications and training) of those delivering interventions

6.56

1.57

24

29. Engaging stakeholders in the selection of outcomes (New item in survey 2)

N/A

N/A

N/A

30. Methods for cost-effectiveness analyses for behavioral trials

6.43

1.56

26

31. Trials’ research to test and develop behavioral theories

6.45

1.70

25

32. Strategies for handling missing data within behavioral trials

6.26

1.80

27

33. Developing novel statistical techniques to enhance behavioral trials

6.03

1.69

29

34. Blinding of researchers and participants to study arm allocation

6.1

1.90

28

35. Sample-size calculations for pilot studies

5.84

2.30

30