Are you about administering a questionnaire to your program participants? Are you wondering how many of those participants you need to respond to your program survey to be “statistically correct”? In this resource, I am creating a list that shows the sample size you should be considering for your program survey. Krejcie and Morgan in 1970 created this table for determining sample size for a given population for easy reference. But before you jump to the list, let’s clarify some basic statistical jargon.

Angela Mogadishu, the Monitoring and Evaluation Officer at Madagascar Foundation, found out, from the attendant’s register that 2,800 young women attended their 5-day Women Empowerment Bootcamp (WEB). Angela designed a questionnaire to help the Foundation understand the perception of the women that attended WEB. As usual, Angela could not reach out to all the 2,800 young women that attended WEB, so she needed a certain proportion that could represent all the other women. To have a representative statistical sample, Angela chose 350 after referring to the list below. Thus the 2,800 young women are referred to as the population, while the 350 women are the sample size that should actually respond to the questionnaire she has designed.

Wait a minute, a quick look at a population of 2,800 in the list below resulted in a sample size of 338. Why did Angela choose 350? In real-world evaluation, Angela might not get response from all the 338 because of several reasons. So she already assumed she would not get responses from 12 young women that were part of the WEB program. If I were Angela, I would target 360 respondents. Nevertheless, we can all be Angela!

Table for Determining Sample Size for a Finite Population
Population Sample size Population Sample Size Population Sample Size
10 10 220 140 1200 291
15 14 230 144 1300 297
20 19 240 148 1400 302
25 24 250 152 1500 306
30 28 260 155 1600 310
35 32 270 159 1700 313
40 36 280 162 1800 317
45 40 290 165 1900 320
50 44 300 169 2000 322
55 48 320 175 2200 327
60 52 340 181 2400 331
65 56 360 186 2600 335
70 59 380 191 2800 338
75 63 400 196 3000 341
80 66 420 201 3500 346
85 70 440 205 4000 351
90 73 460 210 4500 354
95 76 480 214 5000 357
100 80 500 217 6000 361
110 86 550 226 7000 364
120 92 600 234 8000 367
130 97 650 242 9000 368
140 103 700 248 10000 370
150 108 750 254 15000 375
160 113 800 260 20000 377
170 118 850 265 30000 379
180 123 900 269 40000 380
190 127 950 274 50000 381
200 132 1000 278 75000 382

Source: Krejcie and Morgan, (1970) Determining Sample Size for Research Activities. Educational and Psychological Measurement

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