Menu
Home
Log in / Register
 
Home arrow Environment arrow Research Methods in Anthropology: Qualitative and Quantitative Approaches
Source

SAMPLING PROBLEMS

There are five questions to ask when drawing a sample for a TA study:

  • 1. Who do I watch?
  • 2. Where do I go to watch them?
  • 3. When do I go there?
  • 4. How often do I go there?
  • 5. How long do I spend watching people when I get there? (Gross 1984)

Allen Johnson’s study (1975) of the Machiguenga is instructive. The Machiguenga are horticulturists in the Peruvian Amazon. They live along streams, in small groups of related families, with each group comprising from about 10 to 30 people, and subsist primarily from slash-and-burn gardens. They supplement their diet with fish, grubs, wild fruits, and occasional monkeys from the surrounding tropical forest. Johnson spent 14 months studying the Machiguenga in the community of Shimaa.

Johnson’s strategy for selecting people to study was simple: Because all travel was on foot, he decided to sample all the households within 45 minutes of his own residence. This produced a convenience sample of 13 households totaling 105 persons. The Machi- guenga live along streams, so each time Johnson went out he walked either upstream or downstream, stopping at a selected household along the route. He selected the hour of the day to go out and the houses to vist at random.

Thus, Johnson used a nonrandom sample of all Machiguenga households, but he randomized the times that he visited any household in his sample. This sampling strategy sacrificed some external validity, but it was high on internal validity. Johnson could not claim that his sample of households statistically represented all Machiguenga households. His 14 months of experience in the field, however, makes his claim for the representativeness of his data credible.

That is, if Johnson’s data on time allocation in those 13 households seem to him to reflect time allocation in Machiguenga households generally, then they probably do. But we can’t be sure. Fortunately, randomizing his visits to the 13 households, and making a lot of observations (3,945 of them, over 134 different days during the 14-month fieldwork period), gives Johnson’s results a lot of internal validity. So, even if you’re skeptical of the external validity of Johnson’s study, you could repeat it (in Shimaa or in some other Machiguenga community) and see whether you got the same results.

Regina Smith Oboler (1985) did a TA study among the Nandi of Kenya. She was interested in differences in the activities of adult men and women. The Nandi, Oboler said, “conceptualize the division of labor as sex segregated. Is this true in practice as well? Do men and women spend their time in substantially different or similar types of activities?” (p. 203).

Oboler selected 11 households, comprising 117 people, for her TA study. Her sample was not random. ‘‘Selecting a random sample,’’ she said, ‘‘even for one kokwet (neighborhood) would have made observations impossibly difficult in terms of travel time’’ (Oboler 1985:204). Instead, Oboler chose a sample of households that were matched to social and demographic characteristics of the total population and within half an hour walking distance from the compound where she lived.

Oboler divided the daylight hours of the week into 175 equal time periods and gave each period (about 2 hours) a unique three-digit number. Then, she chose time periods at random from the list of 175 numbers to visit each household. She visited each household four times a week (on different days of the week) during 2 weeks each month and made nearly 1,500 observations on those households during her 9 months in the field.

Oboler found that, for her sample of observations, adult men spend around 38% of their time ‘‘in activities that might reasonably be considered ‘work’ by most commonly used definitions of that term’’ (Oboler 1985:205). Women in her sample spent over 60% of their time working.

 
Source
Found a mistake? Please highlight the word and press Shift + Enter  
< Prev   CONTENTS   Next >
 
Subjects
Accounting
Business & Finance
Communication
Computer Science
Economics
Education
Engineering
Environment
Geography
Health
History
Language & Literature
Law
Management
Marketing
Mathematics
Political science
Philosophy
Psychology
Religion
Sociology
Travel