Background
Methods
Criteria for considering studies for this review
Types of studies
Population
Types of methods
Types of outcome measures
Search methods
Data extraction
Assessment of risk of bias in included studies
Data analysis
Results
Study ID | Aims of study | Study sample | Study topic | Study design | Total number of subjects in study (N) | Control (n) | Intervention (n) | Country |
---|---|---|---|---|---|---|---|---|
Akl et al., 2011 [41] | Assess the effect of 1) tracking responses and 2) day of mailing (Monday vs Friday) on physician survey response rate | Directors of Family Medicine residency programs (ie GPs) | Training of residents in implementation of clinical guidelines | Two by two factorial randomized design | 456 | No tracking n = 228, Monday mailing n = 228 | Tracking n = 228, Friday mailing n = 228 | USA |
Asch et al., 1998 [26] | To evaluate the effect of incentive size by providing physicians either a $5 bill or a $2 bill. | Primary care physicians identified from the American Medical Association Physician Master File | Attitudes about cost containment in cancer screening. | RCT | 1000 | $2 cash incentive received in initial mailing n = 500 | $5 cash incentive received in initial mailing n = 500 | USA |
Baron et al., 2001 [29] | To evaluate the cost effectiveness of a lottery on physicians response rates to a mail survey. | Family Doctors identified from membership list of the Quebec Federation of GPs | The determinants of influenza immunization among family physicians in Quebec. | RCT | 1000 | No lottery n = 500 | Lottery n = 500 | Canada |
Bonevskiet al., 2011 [40] | To examine the efficacy of two strategies for improving general practitioner response to a survey and a secondary aim was to assess GPs self reported preferred mode of survey administration. | GPs practising in NSW selected from the Australasian Medical Publishing Company database. | The knowledge, attitudes and practices of GPs around vitamin D. | RCT | 334 (Cover letter trial), 1166 (Telephone reminder trial) | Standard cover letter N = 167, No telephone reminder n = 576 | Standard letter plus local division of general practice cover letter n = 167, Telephone reminder n = 590 | Australia |
Deehan et al., 1997 [11] | To explore the effects of financial and non-financial inducements on response rates to increase the overall response rate. | A random sample of all GP’s in England and Wales. | Survey on GP’s work and attitudes with alcohol misusing patients. | Five arm parallel trial design with randomization | 3584 | No inducement n = 1188 | £5 charity donation n = 607, £10 charity donation n = 578, £5cash payment n = 613, £10 cash payment n = 598, (Total for all interventions n = 2396) | UK |
Drummond et al., 2008 [34] | To investigate the effect of two low cost interventions (pre-contact and questionnaire order) on response to a primary care physician postal survey | Primary care physicians working in Ireland identified from various sources. | A national survey assessing views and practices of physicians regarding prostate specific antigen (PSA) testing. | Two by two factorial randomized design | 1599 | No pre-contact n = 743, Version 2 survey (Topic specific questions first) n = 744 | Pre-contact n = 715, Version 1 survey (general questions first) n = 714 | Ireland |
Everett et al., 1997 [28] | To examine the effectiveness of $1 incentive on response rates | Family Physicians | Firearm-safety counseling beliefs | RCT | 600 | No incentive n=300 | $1 bill n=300 | USA |
Gattellari et al., 2012 [13] | Assess effectiveness of two response-aiding strategies in a postal survey | GPs known to be in current practice | Management of nonvalvular atrial fibrillation | Two by two factorial randomized control trial | 1000 | Mail prompt n = 500, Coloured seal without text n = 500 | Fax prompt n = 500, Coloured seal + text n = 500 | Australia |
Gupta et al., 1997 [39] | To determine the effectiveness of a telephone prompt by a medical researcher compared to a nonmedical research assistant in improving survey response rate of GP’s, and to compare personnel costs. | A national random sample of Australian GPs | A national survey assessing GPs views of clinical practice guidelines | RCT | 404 | Telephone prompt by a medical researcher n = 202 | Telephone prompt by experienced nonmedical research assistant n = 202 | Australia |
Hocking et al., 2006 [35] | To compare GP response to a telephone interview with response to a postal survey with three reminders. | A random sample of Victorian GPs | Survey to assess knowledge and diagnostic and management practices of genital chlamydia infection. | RCT | 867 | Postal survey n = 451 | Telephone interview n = 416 | Australia |
James et al., 2011 [27] | To study the effects of payment timing, form of payment and requiring a social security number (SSN) on survey response rates. | Practising US physicians ages 65 and under representing all specialties (including primary care), selected from the AMA Physician Masterfile | Survey on ethical and moral beliefs. | Four arm parallel design with randomization | 443 | Promised $US25 check requiring SSN n = 102 | Immediate $US25 cash n = 129, Immediate $US25 check n = 97, Promised $US25 check not requiring SSN n = 115 | USA |
McLaren and Shelley 2000 [30] | To compare effect of a primer telephone call and postcard on GP response rate; and to compare the effect of informing GPs about a prize for participating in survey compared to not informing GPs of the prize. | Victorian GPs | Management issues surrounding early pregnancy bleeding and miscarriage | Two by two factorial design with randomization | 621 | Telephone n=305 No prize notification N=310 | Postcard n=316Prize notification n=311 | Australia |
Maheux et al., 1989 [42] | To determine the response rates of Quebec physicians by sending a handwritten thank you letter and by sending a more personalized mailout package. | Quebec Physicians | To determine the level of physicians support for a number of patient care issues. | RCT | Second mailing N = 356, Third mailing N = 253 | No handwritten postscript n = 186, Non-personalised mailout n = 127 | Handwritten postscript n = 170, Personalised mailout n = 126 | Canada |
Olivarius and Andreasen, 1995 [43] | To test a possible day the week effect on doctors response rate to a postal questionnaire. | GPs | A nationwide survey on doctors’ attitude on the relative importance of general practice and the specialties in the treatment of general diseases and diseases commonly regarded as belonging to the specialties. | RCT | 200 | Dispatch of survey on Thursday (for receipt before weekend) n = 98 | Dispatch of survey on Saturday (for receipt after weekend) n = 102 | Denmark |
Pedrana et al., 2008 [44] | To compare response rates to postal surveys sent by normal post and registered mail and to assess the cost implications of the two mailing methods. | General practitioners in Victoria. | To assess antenatal screening practices in Australia | RCT | 1550 | Normal mail n = 775 | Registered mail n = 775 | Australia |
Pirotta et al., 1999 [38] | To measure the effect of a primer postcard to improve mailed survey response rates. | Victorian GPs who had at least 1500 consultations in 1995-96 | General Practitioners attitudes to complementary therapies. | RCT | 800 | No primer postcard n = 400 | Primer postcard n = 400 | Australia |
Pit et al., 2013 [25] | To assess the effectiveness of small non-conditional non-financial incentive (ie attractive pen) on survey response rates | Practicing GPs in Northern Rivers region of NSW | How to improve sustainable employment of ageing GPs in rural Australia | RCT | 125 | No pen incentive n = 62 | Pen incentive n = 63 | Australia |
Robertson et al., 2005 [31] | To test the effect of a $AUD2 scratch lottery ticket on response rates | A random sample GP’s and specialists from the medical directory of Australia. | To explore the uptake of 19 new drugs into the clinical practices of Australian GPs and specialists. | RCT | 464 | No lottery n = 232 | AUD$2 scratch lottery n = 232 | Australia |
Scott et al., 2011[24] | To compare effects and costs of three different modes of survey administration in a national survey of Doctors | A stratified random sample of doctors undertaking clinical practice from a national directory of all doctors in Australia. Stratification was by doctor type and rural/remote category. | Study of the dynamics of the medical labour market in Australia, focusing on workforce participation and its determinants among Australian doctors. | 3-arm parallel trial design with randomisation | 1091 | Online survey, followed by reminder letter with login details n = 369 | Sequential mixed mode -online survey, followed by reminder letter with paper survey n = 388, Simultaneous mixed mode -paper survey and login details sent together, with reminder letter with login details n = 334 | Australia |
Seguin et al., 2004 [37] | To compare email with regular mail for conducting surveys of family physicians. | A random sample of physicians listed in the college of family physicians of Canada’s database who had an email address | Survey on use of sildenafil citrate (Viagra) | RCT | 2397 | Survey delivered by post to the physicians without email n = 800 | Survey delivered by email n = 798, Survey delivered by post to the physicians with e mail n = 799 | Canada |
Shosteck and Fairweather, 1979 [36] | Comparison of mail and personal administration of questionnaire among physicians. | Office-based primary care physicians who were in active practice within the States of Washington DC and Maryland, and treating upper respiratory or lower urinary tract infections selected from the AMA database. | Physician antibiotic prescription practices. | RCT | 543 | Mail technique n = 296 | Personal interview technique n = 247 | USA |
Thomson et al., 2004 [32] | To maximise the response to a postal questionnaire and to test the most effective form of incentive. | Practicing GP’s selected from the Lothian Primary Care NHS Trust database. | GP’s attitudes to the management of ingrowing toenails. | RCT | 568 | Lottery of one chance to win six bottles of champagne n = 286 | Lottery of six chances to win one bottle of champagne n = 282 | UK |
Ward et al., 1998 [33] | To evaluate response aiding strategies feasible in large surveys | Randomly selected sample of general practitioners | Cancer screening | 4-arm parallel trial design with randomisation | 1550 | - | Doctor advance phone prompt: n = 249, Pen prompt: n = 261, Letter prompt: n = 260, Non-doctor advance phone prompt: n = 501 | Australia |
Study ID | Allocation concealed? | Randomisation performed? | Blinding of participants & personnel? | Complete outcome data? | Absence of reporting bias? | Absence of other bias? | ITT analysis? |
---|---|---|---|---|---|---|---|
Monetary incentives
| |||||||
1. Asch et al., 1998 [26] | ? | √ | ? | √ | √ | √ | √ |
2. Deehan et al.,1997 [11] | ? | √ | ? | ? | √ | ? | √ |
3. Everett et al.,1997 [28] | ? | √ | ? | √ | √ | ? | √ |
4. James et al., 2011 [27] | ? | √ | ? | ? | √ | √ | X |
Non-monetary incentives
| |||||||
5. Baron et al., 2001 [29] | ? | √ | ? | ? | √ | √ | √ |
6. McLaren and Shelley, 2000 [30] | ? | √ | ? | ? | √ | ? | X |
7. Pit et al., 2013 [25] | X | √ | X | ? | √ | √ | √ |
8. Robertson et al.,2005 [31] | ? | √ | ? | √ | √ | ? | √ |
9. Thomson et al.,2004 [32] | ? | √ | ? | ? | √ | ? | √ |
Questionnaire design/ mode of delivery
| |||||||
10. Drummond et al., 2008 [34] | √ | √ | ? | √ | √ | √ | √ |
11. Hocking et al., 2006 [35] | X | √ | ? | √ | √ | ? | √ |
12. Shosteck and Fairweather,1979 [36] | ? | √ | ? | √ | √ | √ | √ |
13.Seguin et al.,2004 [37] | ? | √ | ? | √ | √ | ? | √ |
14. Scott et al., 2011 [24] | X | √ | X | ? | √ | √ | √ |
Other design based strategies
| |||||||
15. Akl et al., 2011 [41] | X | √ | ? | ? | √ | ? | √ |
16. Bonevski et al., 2011[40] | ? | √ | ? | ? | √ | ? | √ |
17. Gattellari et al., 2012[13] | X | √ | X | ? | √ | √ | √ |
18. Gupta et al.,1997 [39] | ? | √ | ? | ? | √ | ? | √ |
19. Maheux et al., 1989[42] | ? | √ | ? | ? | √ | ? | √ |
20. Olivarius and Andreasen, 1995 [43] | X | √ | ? | √ | √ | ? | √ |
21. Pedrana et al.,2008 [44] | X | √ | ? | ? | √ | ? | √ |
22. Pirotta et al.,1999 [38] | √ | √ | √ | √ | √ | ? | √ |
23. Ward et al., 1998 [33] | X | √ | ? | √ | √ | √ | √ |
Incentives
Monetary incentives
Monetary incentives | Intervention | OR | 95%CI |
---|---|---|---|
Deehan et al., 1997 [11] | £10 vs no incentive | 3.14 | 2.37, 4.15 |
£5 vs no incentive |
2.22
| 1.66, 2.98 | |
£10 charity donation vs no incentive |
1.20
| 0.85, 1.69 | |
£5 charity donation vs no incentive | 1.12 | 0.79, 1.57 | |
Pooled (Deehan, 1997)
|
1.87
|
1.48, 2.36
| |
Everett et al., 1997 [28] | $1bill vs no incentive | 1.86 | 1.34, 2.57 |
Pooled
|
1.87
|
1.55, 2.26
| |
Nonmonetary incentives
| |||
Baron et al., 2001 [29] | Lottery to win weekend trip vs No incentive | 1.31 | 1.02, 1.70 |
McLaren and Shelley, 2000 [30] | Awareness of prize vs no awareness of prize | 1.17 | 0.84, 1.61 |
Pit et al., 2013 [25] | Pen vs no incentive | 1.85 | 0.91, 3.77 |
Robertson et al., 2005 [31] | AU$2 Lottery vs no incentive | 1.78 | 1.23, 2.60 |
Pooled
|
1.39
|
1.15, 1.69
| |
Large vs small incentives
| |||
Asch et al., 1998 [26] | US$5 vs US$2 | 1.83 | 1.43, 2.35 |
Deehan et al., 1997 [11] | £10 cash vs £5 cash | 1.41 | 1.06,1.87 |
£10 charity donation vs $5 | 1.08 | 0.73,1.58 | |
Thomson et al., 2004 [32] | Lottery to win a large prize (6 bottles of champagne) vs six chances to win one bottle | 1.47 | 1.05, 2.08 |
Pooled
|
1.47
|
1.19,1.81
| |
Prepaid vs promised incentives
| |||
James et al., 2011 [27] | US$25 prepaid vs US$25 promised | 2.88 | 1.70, 4.89 |
Nonmonetary incentives
Size of incentives
Design based strategies
Questionnaire design | Intervention | OR | 95% CI |
---|---|---|---|
Drummond et al., 2008 [34] | General questions vs topic related questions first | 1.17 | 0.96, 1.43 |
Survey delivery mode
|
Intervention
| ||
Hocking et al., 2006 [35] | Postal survey vs telephone interview | 2.66 | 2.02, 3.52 |
Shosteck and Fairweather, 1979 [36] | Postal survey vs telephone interview | 1.03 | 0.68, 1.55 |
Seguin et al., 2004 [37] | Postal survey vs email survey | 2.00 | 1.67, 2.38 |
Pooled
|
1.82
|
1.19, 2.78
| |
Scott et al. 2011 [24] | Online survey vs mixed mode | 0.73 | 0.51, 1.04 |
Online survey vs sequential mixed mode | 0.65 | 0.44, 0.97 | |
Online survey vs Simultenous mixed mode | 0.83 | 0.55, 1.26 | |
Advance contact
| |||
Drummond et al., 2008 [34] | Letter pre-contact letter vs no pre-contact | 1.10 | 0.91, 1.35 |
Pirotta et al., 1999 [38] | Postcard pre-contact vs no pre-contact | 1.30 | 0.98, 1.72 |
Pooled
|
1.16
|
0.99, 1.37
| |
Gattellari et al., 2012 [13] | Mail pre-contact vs fax pre-contact | 1.11 | 0.87, 1.43 |
McLaren and Shelley, 2000 [30] | Telephone pre-contact vs postcard pre-contact | 1.01 | 0.73, 1.40 |
Gupta et al., 1997 [39] | Medical researcher pre-contact vs non-medical researcher | 1.33 | 0.87, 2.05 |
Ward et al., 1998 [33] | GP phonecall pre-contact vs other interventions | 1.39 | 1.02, 1.88 |
Pen pre-contact vs other interventions | 0.97 | 0.73, 1.30 | |
Letter pre-contact vs other interventions | 0.95 | 0.71, 1.26 | |
Research assistant phonecall pre-contact vs other interventions | 0.86 | 0.68, 1.09 | |
Reminders
| |||
Bonevski et al., 2011 [40] | Telephone reminder vs none | 1.21 | 0.68, 2.15 |
Tracking
| |||
Akl et al., 2011[41] | Tracking of reponses for follow up vs No tracking | 0.85 | 0.59, 1.23 |
Personalisation and GP group endorsed letters
| |||
Bonevski et al., 2011[40] | Sponsorship letter vs standard letter 1st mailout | 1.38 | 0.86, 2.22 |
Gattellari et al., 2012 [13] | Coloured seal with text vs coloured seal without text | 1.08 | 0.84, 1.38 |
Maheux et al., 1989[42] | Handwritten ‘thank you’ postscript with 1st reminder vs no postscript | 1.45 | 0.92, 2.30 |
Maheux et al., 1989[42] | Personalised mail out package vs Non-personalised mail out package with 2nd reminder | 1.73 | 1.04, 2.87 |
Timing of mailing
| |||
Akl et al., 2011[41] | Friday vs onday mailing | 1.86 | 1.28, 2.69 |
Olivarius and Andreasen, 1995 [43] | Saturday vs Thursday mailing | 0.55 | 0.25, 1.23 |
Pooled
|
1.07
|
0.33, 3.50
| |
Type of mailing
| |||
Pedrana et al., 2008 [44] | Registered mail vs standard mail | 2.97 | 2.31, 3.81 |