Russel-Research-Method-in-Anthropology

162 Chapter 6
along the lines and don’t have enough cases, you can take another random
start, with the same or a different interval and start again. Be careful of periodicity,
though.
Camilla Harshbarger (1995) used another variation of map sampling in her
study of farmers in North West Province, Cameroon (1993). To create a sample
of 400 farmers, she took a map of a rural community and drew 100 dots
around the perimeter. She used a random number table to select 50 pairs of
dots and drew lines between them. She numbered the points created by the
crossing of lines, and chose 80 of those points at random. Then, Harshbarger
and her field assistants interviewed one farmer in each of the five compounds
they found closest to each of the 80 selected dots. (If you use this dot technique,
remember to include the points along the edges of the map in your
sample, or you’ll miss households on those edges.)
There are times when a random, representative sample is out of the question.
After Harshbarger did those interviews with 400 randomly selected farmers
in North West Province, Cameroon, she set out to interview Fulani cattle
herders in the same area. Here’s what Harshbarger wrote about her experience
in trying to interview the herders:
It was rainy season in Wum and the roads were a nightmare. The grazers lived
very far out of town and quite honestly, my research assistants were not willing
to trek to the compounds because it would have taken too much time and we
would never have finished the job. I consulted X and he agreed to call selected
people to designated school houses on certain days. We each took a room and
administered the survey with each individual grazer.
Not everyone who was called came for the interview, so we ended up taking
who we could get. Therefore, the Wum grazer sample was not representative and
initially that was extremely difficult for me to accept. Our team had just finished
the 400-farmer survey of Wum that was representative, and after all that work it
hit me hard that the grazer survey would not be. To get a representative sample,
I would have needed a four-wheel drive vehicle, a driver, and more money to pay
research assistants for a lengthy stay in the field. Eventually, I forgave myself for
the imperfection. (personal communication)
The lessons here are clear. (1) If you are ever in Harshbarger’s situation,
you, too, can forgive yourself for having a nonrepresentative sample. (2) Even
then, like Harshbarger, you should feel badly about it. (For more on space
sampling, see Daley et al. 2001 and Lang et al. 2004.)
Maximizing Between-Group Variance: The Wichita Study
Whenever you do multistage cluster sampling, be sure to take as large a
sample as possible from the largest, most heterogeneous clusters. The larger