Recruiting Phobic Research Subjects: RESULTS

In: Anesthesia

24 Dec 2009

Recruitment Outcomes

A total of 911 people contacted the study coordinator. From these initial contacts, 186 (20.4%) were not interested in a study, 165 (18.1%) were rejected (78 during the telephone interview and 87 later), and 530 (58.2%) expressed interest in the study and appeared qualified. Thirty individuals (3.3%) called because they wanted to refer someone else. The frequency of initial contacts, subjects’ interest, rejected recruits, and subjects calling for others are presented in Table 1 for each recruitment method. Of 619 subjects who received the study material, 290 returned the study questionnaire. Two hundred prospective subjects were interviewed, with 166 accepted for participation. Twenty-two subjects (2.4%) withdrew during the study and needed to be replaced. However, only 9 of these 22 subjects actually took the study drug and actually started the study before withdrawing. One hundred forty-four subjects were enrolled for the study, which is 20.7% of the 695 subjects (530 interested ones and 165 rejected ones) who were interested in participating in the study. Similarly, 23.3% of 617 subjects who received the study materials (the questionnaire and the brochure) and 72.0% of screened subjects were enrolled. Of 911 prospective subjects who initially contacted the research coordinator, 15.8% (144/911) were enrolled.

Table 1. The Initial Recruitment Outcomes by Recruitment Method

Rejected

(Phone N = 78,

Initial

Interested

Screening

Not Interested Referring

Contacts

in Study

N = 87;

in Study Others

Recruitment Method

(N = 911)

(N = 530)

N = 165)

(N = 186) (N = 30)
Paid advertising
Bus advertisment

273

182

41

43

7

Open house

1

1

0

0

0

Newspaper

129

65

34

25

5

Campus poster

148

94

29

19

6

Radio

18

9

4

2

3

Free publicity
Internet

3

3

0

0

0

TV

57

29

14

11

3

Word of mouth

78

56

15

5

2

Professional referral
Fears clinic

40

30

6 00

1

Previous research project

10

8

2

0

0

Professional referral

16

8

6

2

0

Unknown

138

45

14

76

3

Paid advertising yielded the majority of the 144 enrolled subjects (63.2%, 91/144). The most effective methods using paid advertising were bus advertisements (42.9%, 39/91), posters on the campus (31.9%, 29/ 91), and newspaper advertisements (20.9%, 19/91). The percentages of the enrollees recruited using free publicity and professional referral were 18.8% (27/144) and 14.6% (21/144), respectively. From the total population, 4.6% reported hearing about the study from 2 sources and 1.2% of the prospective enrollees reported 3 sources. The enrollment was more successful during winter and fall quarters than during summer and spring quarters. Recruitment outcomes are shown in Table 2.

Table 2. The Final Recruitment Outcomes by Recruitment Method

Recruitment Method

Sent study materials (%) (N =617)

Returned questionnaire (%) (N = 290)

Interviewed for study (%) (N = 200)

Accepted into study (%) (N = 166)

Participated (%) (N = 144)
Paid advertising
Bus advertisment 213 (34.4) 102 (35.2)

53 (26.5)

45 (27.1)

39 (27.1)

Open house 1 (0.2) 1 (0.2)

1 (0.5)

1 (0.6)

1 (0.7)

Newspaper 81 (13.1) 33 (11.4)

28 (14.0)

20 (12.0)

19 (13.2)

Campus poster 112(18.1) 54 (18.6)

44 (22.0)

35 (21.1)

29 (20.1)

Radio 9 (1.5) 4 (0.6)

3 (1.5)

3 (1.8)

3 (2.1)

Free publicity
Internet 3 (0.5) 2 (0.7)

2 (1.0)

2 (1.2)

2 (1.4)

TV 33 (5.3) 16 (5.5) 12 (6.0) 11 (6.6)

8 (5.6)

Word of mouth 65 (10.5) 32 (11.0)

23 (11.5)

19 (11.4)

17 (11.8)

Professional referral
Fears clinic 34 (5.5) 20 (6.9) 16 (8.0) 15 (9.0) 12 (8.3)
Previous research project 10 (1.6) 6 (2.1)

6 (3.0)

5 (3.0)

5 (3.5)

Professional referral 10 (1.6) 6 (2.1)

5 (2.5)

4 (2.4)

4 (2.8)

Unknown 46 (7.5) 14 (4.8)

7 (3.5)

6 (3.6)

5 (3.5)

Sixty-four percent of 144 subjects (92/144) enrolled were female. The age of enrollees ranged from 18 to 66 years (mean 37 years). Fifty-five percent (79/144) had completed some college, 45.8% (66/144) had completed college, and 9.7% (14/144) had a graduate degree. The majority (73.4%, 105/143) were white and 21.7% (31/143) were African-Americans. The remaining subjects represented diverse racial backgrounds.
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Women were more often enrolled through paid advertising and free publicity sources. Fifty-one of 91 subjects (56.0%) enrolled using paid advertising and 23 of 27 subjects (85.2%) enrolled using free publicity methods were women (x2 = 4.0, P < .05; x2= 6.7, P < .01, respectively). Equivalent numbers of men and women were enrolled through professional referral. In general, the level of education did not differ by recruitment method or source. However, posters were placed primarily on the campus and thus a greater proportion of the subjects who were enrolled using posters had completed college or had a graduate degree (69.0%) (x2 = 9.2, P < .002). Thirteen of 39 (33.3%) subjects enrolled through bus advertisements had completed college or had a graduate degree (x2 = 3.7, P < .05) Subjects enrolled using bus advertisement were slightly older (40.6 ±10.8 years) than subjects recruited using other methods (34.9 ± 12.2 years, t(135) = -2.6, P < .01).

The majority of African-Americans (82.8%) were recruited using paid advertising, while 64.3% of whites were recruited using these methods (x2 = 3.5, P < .06). Of African-American participants, 53.3% (16/30) were recruited through bus advertisements, 6 were enrolled through newspaper advertisement, 2 using campus posters, 4 using professional referral methods, and 2 through free publicity. The proportion of whites (20.0%, 20/100) enrolled through bus advertisements was significantly lower than African-Americans (53.3%, 16/30, x2 = 13.8, P < .0002). However, the multiple routes of advertising increased the overall diversity of the subject population.
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Cost of Advertising

The newspaper advertising ranged from $25 to $369 (1996 dollars) depending on the newspaper and the size of the ad. Bus advertisements ranged from $450 to $1559 depending on the number of buses in each campaign. The cost of poster advertising was estimated as man-hours spent by student staff in copying and placing posters around the campus. Approximately 4 hours were spent monthly for this at $7 per hour. TV, Internet, open house, previous research projects, and word of mouth involved minimal costs. Except for 1 journal, the advertising in professional journals was free. The total cost of advertising for each method used and the advertising costs per individual subject enrolled are given in Table 3. The average cost per subject enrolled was $79 ($11,483/144 subjects enrolled).


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