Table 1 Responses

Overall references in systematic review:

n = 75

Excluded references or questionnaires not sent:

11/75 (15%)

 No valid e-mail address found

2/75 (3%)

 Not transformed into questionnaire*

4/75 (6%)

 Explicit rejection in pilot survey**

3/75 (4%)

 No reaction in pilot survey**

1/75 (1%)

 Unburden author who was already in pilot survey**

1/75 (1%)

Questionnaires sent (vs. overall references):

64/75 (85%)

 Pilot survey

9/75 (12%)

 Main survey

55/75 (73%)

Overall responses (vs. questionnaires sent):

19/64 (30%)

 Completed responses:

13/64 (20%)

 Incompleted responses:

5/64 (8%)

 Other responses:

1/64 (2%)

No responses (vs. questionnaires sent):

45/64 (70%)

Adjusted response rate (only completed responses):

13/64 (20%)