Choosing Effective Evaluation Methods

s a practitioner, you have been convincedthat you should evaluate your program. Youhave talked with stakeholders about whatpurposes they have for the evaluation. Stake-holders and evaluators have agreed on the elements andpurpose of the program to be evaluated as well as thepriority questions to be answered. You have focusedthe evaluation and determined an evaluation design.Now it is time to select appropriate methods for obtain-ing evaluation information.The many possible methodologies make it diffi-cult for the practitioner to choose. The focus of this is-sue’s column is on identification of basic types of data-gathering strategies, strengths and weaknesses of each,and variables to consider in making choices.TWO ISSUES IN DATA COLLECTIONThere are at least two issues that form recurringthemes in evaluation and should be discussed here. Thefirst is the use of quantitative and qualitative data col-lection methods (Bernard, 1998; Green & Lewis, 1986;Patton, 1990; Shadish, Cook, & Leviton, 1991). All de-bates about these issues aside for the moment, each ap-proach has advantages for answering certain kinds ofquestions. Table 1 has some detailed information aboutthe advantages and disadvantages of qualitative andquantitative measures. An upcoming article in thisEvaluation in Practice column will discuss that atgreater length. Most of the suggested types of measuresdiscussed here will be a mix of qualitative (e.g., focusgroupinterviewsorfieldobservations)andquantitative(e.g., physiological measures and questionnaires)measures.The second is the use of obtrusive and nonobtrusivemeasures (Bernard, 1998; Shadish et al., 1991). Obtru-sive measures are those that are completed in the open,or in plain view, and with the direct knowledge of theparticipants. Unobtrusive measures are those that aredone in the absence of direct awareness by participants,althoughtheydonotprecludepriorknowledgeandper-mission by participants. Obtrusive measures might in-clude surveys and diaries. Unobtrusive measures mightinclude key informant interviews, as well as direct ob-servation of public behaviors.STRATEGIES FOR GATHERING EVALUATION DATAAlthough a myriad of data-gathering methods andvariationsexists,itmaybehelpfultobeginbygroupingthem according to obtrusive (interactive) and unobtru-sive (noninteractive) methods. A data-gathering methodmayinvolveactualmeasurementoraskingquestionsofpeople in an interactive way, or obtaining informationwithout direct participant input. Consideration shouldalso be given to whether qualitative, quantitative, ormixed-method approaches are best for the situation.Physiological MeasuresPerhaps the most objective means of gathering eval-uation information is to take direct physiological mea-surements of individuals (Cooper, Heron, & Heward,1987;Green&Lewis,1986).Forexample,measuresofthe effectiveness of a 6-month fitness walking programmight include blood pressure, serum cholesterol, andrecovery heart rate. A program designed to improve thehealth status of newborns may include measuring thebirth weight of all infants born to mothers involved inan experimental program or control group. Althoughdirect physiological measures can provide clear quanti-