Toward a Causal Model Approach for Adjusting for Preexisting Differences in the Nonequivalent Control Group Situation

Jay Magidson
Additional contact information
Jay Magidson: Abt Associates, Inc.

Evaluation Review, 1977, vol. 1, issue 3, 399-420

Abstract: The traditional approach for partialing out the effects of confounding factors in a non equivalent control group situation is to calculate a partial correlation coefficient or a (partial) regression coefficient controlling for one or more "covariates." Since the covariates generally are imperfect measures of the factors, this procedure will typically yield biased estimates of effect. An alternative approach, which allows for the presence of measurement error, is discussed and applied to some data from the original Head Start evaluation. Contrary to the original analysis, which found the Head Start program to be totally ineffective, the alternative approach yields small positive estimates of effect. The resulting model is conceptually feasible and fits the data well. However, it is only one of many possible causal models which could have been formulated. Guidelines are needed for building causal models in the evaluation research framework when little is known a priori regarding the causal relationships.

Date: 1977
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://journals.sagepub.com/doi/10.1177/0193841X7700100303 (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:sae:evarev:v:1:y:1977:i:3:p:399-420

DOI: 10.1177/0193841X7700100303

Access Statistics for this article

More articles in Evaluation Review
Bibliographic data for series maintained by SAGE Publications ().