Journal of Clinical Epidemiology 67 (2014) 482e483
LETTER TO THE EDITOR A charitable donation incentive did not increase physician survey response rates in a randomized trial Strategies to improve physician survey response rates are needed. Promised charitable donations might appeal to the respondent’s sense of altruism, by allowing them to support an organization with which they share common goals and values [1]. We conducted a randomized trial comparing the effect of a $40 charitable donation to the Kidney Foundation of Canada with no incentive on response rates in a survey of nephrologists’ attitudes toward home dialysis. Our sampling frame consisted of all practicing nephrologists in Canada, drawn from provincial registers, and listservs. We used a computerized random number generator and stratified by province to randomize nephrologists in a 1:1 ratio to receive the incentive vs. standard notifications with no incentive. We used a modified Tailored Design Method [2], with prenotification, invitation, first reminder, and final reminder letters sent by e-mail to both groups simultaneously over a 4-week period. Letters were identical for both groups with the exception of the following phrase: ‘‘By completing the survey, and in compensation for your time, a charitable donation of $40 CAD will be made, on your behalf, to the Kidney Foundation of Canada, by our study sponsors.’’ We used a commercial web-based survey platform (Fluid Surveys). Characteristics of study participants are presented in Table 1. Among 484 eligible participants, 81 of 241 (33.6%) vs. 93 of 243 (38.3%) responded in the intervention and control groups, respectively (relative risk Z 1.10, 95% confidence interval [CI]: 0.85e1.42, P Z 0.46). In a time-to-event analysis (Cox regression), the hazard ratio was 1.15 (95% CI: 0.83e1.48, P Z 0.51); we found no significant interaction between respondent characteristics and the intervention. Financial disclosure: Three major dialysis equipment manufacturers (Fresenius Medical Care, Baxter Healthcare, and Gambro Canada) provided equal financial support for the study. Each sponsor paid a one-third share of a $40 charitable donation directly to the Kidney Foundation of Canada for each survey response we received. Funding was provided by the Canadian Nephrology Knowledge Generation and Translation Network, who is supported jointly by Canadian Institutes of Health Research (FRN# 251048) and the Kidney Foundation of Canada for support of L.B.’s work on survey administration. The investigators received no direct research funding of financial compensation from industry sponsors. The study sponsors had no role in study design, administration, analysis, or reporting. 0895-4356/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved.
Our findings are consistent with those of at least one other study. Gattellari and Ward [3], in a study of Australian surgeons, found that a promised charitable donation of $10 AUS to their professional college decreased the response rate. In the Australian study, the control group response rate was 70%, providing little room for improvement. Moreover, unlike our study, the Australian study provided monthly reminders over a 4-month period. Multiple successive reminder prompts may have impacted negatively on participants’ enthusiasm for supporting the study (or the charity) over time. In contrast, we followed a published method that involved four points of contact over a 4-week period [2]. We deliberately restricted our study period and number of prompts to avoid antagonizing participants in our fairly small national community. A more persistent approach may have yielded a higher response rate. Survey fatigue, a lack of interest in the topic, and a perception among participants that they support the Kidney Foundation through other means may explain the ineffectiveness of the incentive. Strengths of this study include its randomized design, balanced respondent characteristics between groups, and the use of a comprehensive (and hence, representative) sample. Limitations include unknown generalizability beyond the Canadian nephrology community and suboptimal sample size. This study adds to a small but important body of evidence suggesting that promised charitable donations might not be effective in improving the response rates in e-mail surveys of physicians. With the growing demands placed Table 1 Characteristics of study participants Characteristics Female gender Practice setting University Community Missing Province Alberta British Columbia Manitoba Maritimes Ontario Quebec Saskatchewan Missing
Intervention (N [ 241)
Control (N [ 241)
n (%)
n (%)
75 (31.1)
73 (30.0)
78 (32.4) 149 (61.8) 14 (5.8)
79 (32.5) 147 (60.5) 17 (7.0)
27 29 10 18 86 61 5 5
(11.2) (12.0) (4.1) (7.5) (35.7) (25.3) (2.1) (2.1)
26 31 8 19 84 66 6 3
(10.7) (12.8) (3.3) (7.8) (34.6) (27.2) (2.5) (1.2)
Letter to the Editor / Journal of Clinical Epidemiology 67 (2014) 482e483
on physicians’ time, better strategies to engage them in survey research are needed and worthy of further study.
David Mendelssohn Department of Nephrology Humber River Hospital 200 Church Street, Toronto Ontario M9N 1N8, Canada
Gihad Nesrallah* The Li Ka Shing Knowledge Institute Keenan Research Centre St. Michael’s Hospital 30 Bond Street, Toronto Ontario, M5B 1W8, Canada Department of Nephrology Humber River Hospital 200 Church Street, Toronto Ontario M9N 1N8, Canada
Lianne Barnieh Braden Manns Department of Medicine Foothills Medical Center 1403d29th St NW, Calgary Alberta T3Z 2T9, Canada
Catherine Clase Department of Health Research Methodology McMaster University 1280 Main Street West Room 2C12, Hamilton Ontario L8S 4K1, Canada
483
Gordon Guyatt Department of Health Research Methodology McMaster University 1280 Main Street West Room 2C12, Hamilton Ontario L8S 4K1, Canada *Corresponding author. Tel: 416-918-2730, Fax: 416-243-4421 E-mail address: [email protected]
References [1] Robertson DH, Bellenger DN. A new method of increasing mail survey responses: contributions to charity. J Market Res 1978;15(4): 632e3. [2] Dilman DA, Smyth JD, Christian LM. Internet, mail, and mixed-mode surveys: the tailored design method. Hoboken, NJ: John Wiley & Sons, Inc.; 2009. [3] Gattellari M, Ward JE. Will donations to their learned college increase surgeons’ participation in surveys? A randomized trial. J Clin Epidemiol 2001;54:645e9. http://dx.doi.org/10.1016/j.jclinepi.2013.11.005
LETTER TO THE EDITOR A charitable donation incentive did not increase physician survey response rates in a randomized trial Strategies to improve physician survey response rates are needed. Promised charitable donations might appeal to the respondent’s sense of altruism, by allowing them to support an organization with which they share common goals and values [1]. We conducted a randomized trial comparing the effect of a $40 charitable donation to the Kidney Foundation of Canada with no incentive on response rates in a survey of nephrologists’ attitudes toward home dialysis. Our sampling frame consisted of all practicing nephrologists in Canada, drawn from provincial registers, and listservs. We used a computerized random number generator and stratified by province to randomize nephrologists in a 1:1 ratio to receive the incentive vs. standard notifications with no incentive. We used a modified Tailored Design Method [2], with prenotification, invitation, first reminder, and final reminder letters sent by e-mail to both groups simultaneously over a 4-week period. Letters were identical for both groups with the exception of the following phrase: ‘‘By completing the survey, and in compensation for your time, a charitable donation of $40 CAD will be made, on your behalf, to the Kidney Foundation of Canada, by our study sponsors.’’ We used a commercial web-based survey platform (Fluid Surveys). Characteristics of study participants are presented in Table 1. Among 484 eligible participants, 81 of 241 (33.6%) vs. 93 of 243 (38.3%) responded in the intervention and control groups, respectively (relative risk Z 1.10, 95% confidence interval [CI]: 0.85e1.42, P Z 0.46). In a time-to-event analysis (Cox regression), the hazard ratio was 1.15 (95% CI: 0.83e1.48, P Z 0.51); we found no significant interaction between respondent characteristics and the intervention. Financial disclosure: Three major dialysis equipment manufacturers (Fresenius Medical Care, Baxter Healthcare, and Gambro Canada) provided equal financial support for the study. Each sponsor paid a one-third share of a $40 charitable donation directly to the Kidney Foundation of Canada for each survey response we received. Funding was provided by the Canadian Nephrology Knowledge Generation and Translation Network, who is supported jointly by Canadian Institutes of Health Research (FRN# 251048) and the Kidney Foundation of Canada for support of L.B.’s work on survey administration. The investigators received no direct research funding of financial compensation from industry sponsors. The study sponsors had no role in study design, administration, analysis, or reporting. 0895-4356/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved.
Our findings are consistent with those of at least one other study. Gattellari and Ward [3], in a study of Australian surgeons, found that a promised charitable donation of $10 AUS to their professional college decreased the response rate. In the Australian study, the control group response rate was 70%, providing little room for improvement. Moreover, unlike our study, the Australian study provided monthly reminders over a 4-month period. Multiple successive reminder prompts may have impacted negatively on participants’ enthusiasm for supporting the study (or the charity) over time. In contrast, we followed a published method that involved four points of contact over a 4-week period [2]. We deliberately restricted our study period and number of prompts to avoid antagonizing participants in our fairly small national community. A more persistent approach may have yielded a higher response rate. Survey fatigue, a lack of interest in the topic, and a perception among participants that they support the Kidney Foundation through other means may explain the ineffectiveness of the incentive. Strengths of this study include its randomized design, balanced respondent characteristics between groups, and the use of a comprehensive (and hence, representative) sample. Limitations include unknown generalizability beyond the Canadian nephrology community and suboptimal sample size. This study adds to a small but important body of evidence suggesting that promised charitable donations might not be effective in improving the response rates in e-mail surveys of physicians. With the growing demands placed Table 1 Characteristics of study participants Characteristics Female gender Practice setting University Community Missing Province Alberta British Columbia Manitoba Maritimes Ontario Quebec Saskatchewan Missing
Intervention (N [ 241)
Control (N [ 241)
n (%)
n (%)
75 (31.1)
73 (30.0)
78 (32.4) 149 (61.8) 14 (5.8)
79 (32.5) 147 (60.5) 17 (7.0)
27 29 10 18 86 61 5 5
(11.2) (12.0) (4.1) (7.5) (35.7) (25.3) (2.1) (2.1)
26 31 8 19 84 66 6 3
(10.7) (12.8) (3.3) (7.8) (34.6) (27.2) (2.5) (1.2)
Letter to the Editor / Journal of Clinical Epidemiology 67 (2014) 482e483
on physicians’ time, better strategies to engage them in survey research are needed and worthy of further study.
David Mendelssohn Department of Nephrology Humber River Hospital 200 Church Street, Toronto Ontario M9N 1N8, Canada
Gihad Nesrallah* The Li Ka Shing Knowledge Institute Keenan Research Centre St. Michael’s Hospital 30 Bond Street, Toronto Ontario, M5B 1W8, Canada Department of Nephrology Humber River Hospital 200 Church Street, Toronto Ontario M9N 1N8, Canada
Lianne Barnieh Braden Manns Department of Medicine Foothills Medical Center 1403d29th St NW, Calgary Alberta T3Z 2T9, Canada
Catherine Clase Department of Health Research Methodology McMaster University 1280 Main Street West Room 2C12, Hamilton Ontario L8S 4K1, Canada
483
Gordon Guyatt Department of Health Research Methodology McMaster University 1280 Main Street West Room 2C12, Hamilton Ontario L8S 4K1, Canada *Corresponding author. Tel: 416-918-2730, Fax: 416-243-4421 E-mail address: [email protected]
References [1] Robertson DH, Bellenger DN. A new method of increasing mail survey responses: contributions to charity. J Market Res 1978;15(4): 632e3. [2] Dilman DA, Smyth JD, Christian LM. Internet, mail, and mixed-mode surveys: the tailored design method. Hoboken, NJ: John Wiley & Sons, Inc.; 2009. [3] Gattellari M, Ward JE. Will donations to their learned college increase surgeons’ participation in surveys? A randomized trial. J Clin Epidemiol 2001;54:645e9. http://dx.doi.org/10.1016/j.jclinepi.2013.11.005
