Choices: Program Evaluation, Coursework Example

Describe, in general, when a sample would be needed as a part of an evaluation.

In program evaluations, sometimes samples are selected as part of evaluation. For instance in evaluating CHOICES, samples are needed as part of evaluation when, it is impossible to study each individual in a population when doing research. When it is impossible to carry out direct observation of each individual, the researcher decided to collect data from a subset of individuals and use the observation to make inferences about the whole population (Kish, 1965).

Kish, (1965) provides that Sample populations are used when the researcher wants to know which proportion of the sample has certain characteristic such as demographic feature or specific opinion. Sample population represents the entire population in a research study.

When would you want to use a probability sample?

A probability sample is used when all the elements of sample has an opportunity of being included in the sample e.g. all the persons or households (Kalton, 1983). Additionally, it can be used when the mathematical probability that one of the elements of the sample will be selected can be calculated. Usage of probability sample is not given much credit by researchers because they argue that a particular trait may dominate in as given population by documentation of a since instance which could not be the case if the same documentation was done as various instances (Schuman, Kalton, 1985).

When would a non-probability sample be appropriate?

Non-probability sampling is contrary to a probability sample because with it, the elements are selected on the basis of their availability may be because they volunteered or because of the judgment of the researcher that they be representatives (Kish, 1965).

Reference

Kalton, G. (1983). Introduction to survey sampling. Beverly Hills: Sage Publications.

Kish, L. (1965). Survey sampling. New York: Wiley.

Schuman, H., & Kalton, G. (1985). Survey methods. In G. Lindzey & E. Aronson (Eds.),. Handbook of Social Psychology, Volume 1 (pp.635-697). New York: Random House.