Social Research Methods: Qualitative and Quantitative Approaches

Reasons for Sampling

Sampling Strategies

Conclusion

Qualitative and Quantitative

Sampling

Sampling is a major problem for any type of research. We can’t study every case of

whatever we’re interested in, nor should we want to. Every scientific enterprise tries

to find out something that will apply toeverything of a certain kind by studying

a few examples,the results of the study being, as we say, “generalizable.”

—Howard Becker,Tricks of the Trade,p. 67

REASONS FOR SAMPLING

When we sample, we select some cases to examine
in detail, and then we use what we learn from them
to understand a much larger set of cases. Most, but

not all, empirical studies use sampling. Depending

on the study, the method we use for sampling

can differ. Most books on sampling emphasize its

use in quantitative research and contain applied

mathematics and quantitative examples. The pri-

mary use of sampling in quantitative studies is to

create a representative sample (i.e., a sample,a

selected small collection of cases or units) that

In Promises I Can Keep,an in-depth study of low-income mothers, Edin and Kefalas

(2005) first identified eight low-income neighborhoods in the Philadelphia, Pennsylvania,

area through extensive qualitative fieldwork and quantitative analysis of census data.

Each neighborhood met three selection criteria: at least 20 percent of householders were

below the poverty line, at least 20 percent of all households had a single parent, and each

had a large number of Black, White, and Hispanic residents. In each neighborhood, Edin

and Kefalas recruited half of the mothers to interview through referrals from local experts

(teachers, social workers, public nurses, clergy, business owners, and public housing

officials) and half by posting fliers on public phone booths or personally contacting

mothers on street corners. All mothers had incomes putting them below the poverty

line in the previous year. Edin and Kefalas tried to get a mixture: 50 Whites, 50 African

Americans, and 50 Puerto Ricans, and tried to get one-half over 25 and one-half under

25 years old. They eventually had 162 mothers, 52 whites, 63 African American, and 47

Puerto Rican. Only 40 were over 25 years old, but ages ranged from 15 to 56. They say,

“The resulting sample is not random or representative but is quite heterogeneous” (238).

Sample A small set of cases a researcher selects from

a large pool and generalizes to the population.