MeasurementTopics in MeasurementThe MappingMapping from the Abstract to the MeasurementSources of Error in MeasurementWhat to Do About ErrorPractical things to do about measurementExamples of MeasuresExamples of IndicatorsHow do we generate indicators?Multiple-measure indicatorsTrust and Efficacy over TimeOther Multiple-Variable IndicatorsScaling Or, How to Create Multiple Indicators More GenerallyImagine an unobserved factor that gives rise to observable factorsMeasurement17.871Spring 2006Topics in Measurement•From abstraction to measure•Sources of error•What to do about error•Practical ways to improve measurementThe MappingXYxyexeyTheoryObservationMapping from the Abstract to the Measurement•Some abstract things we try to measure–Alienation–Moral decay–Democracy–Party identification–Fear of defeat–Terrorism–IdeologySources of Error in Measurement•Conceptual or design error•Bad breaks in random sampling•Survey question wording•Transcription, calculation & mechanization errorsWhat to Do About Error•Practice safe data–Know where your data come from–Watch for anomalies–Use multiple measurement techniques–Collect as much data as possible and disaggregatePractical things to do about measurement•Distinction between a measure and an indicator–Measure: straightforward quantification of a variable of interest–Indicator: quantification of a variable that is believed (or known) to be highly correlated with the “real” variable of interestExamples of Measures•Income in $$•Sales of houses in Massachusetts•Age in years•Votes•Number of wars (hmmmmmm…..)•Campaign contributions•Measurement issues tend to focus on the quality of the data-gathering method, especially sampling – e.g. measuring sales of houses in Mass. via realtor records vs official filingsExamples of Indicators•Most measures are really indicators•Public opinion–Party identification–Trust in government–Ideology•Economics–Gross domestic (national) product•Characterizations of political systems–Freedom–Transparency–Democracy•Quality of collegesHow do we generate indicators?•Trust others and hope for the best–GDP, etc.–Presidential approval•Use a single measure and hope for the best (or convince ourselves it’s OK)–7-point ideology scale–7-point party identification scale–Codings of “wars” or “rally events”–Bulletin of the Atomic Scientist “nuclear clock”–US News and World Report ranking of colleges•Use multiple measures creativelyMultiple-measure indicators•“Trust in government” battery–How much of the time do you think you can trust the government in Washington to do what is right?–Would you say the government is pretty much run by a few big interests looking out for themselves or that it is run for the benefit of all the people?–Do you think that people in the government waste a lot of money we pay in taxes, waste some of it, or don’t waste very much of it?–Do you think that quite a few of the people running the government crooked, not very many are, or do you think hardly any of them are crooked?•External political efficacy battery–Sometimes politics and government seem so complicated that a person like me can’t really understand what’s going on–People like me don’t have any say about what the government does–Public officials don’t care much what people like me think.Trust and Efficacy over TimeOther Multiple-Variable Indicators•Americans for Democratic Action Support Scores•Freedom House freedom assessment•MIT Teaching Quality•Transparency International’s “Corruption Perceptions Index”•DNominate ScoresScalingOr, How to Create Multiple Indicators More GenerallyImagine an unobserved factor that gives rise to observable factors•Democracy•Healthiness•Racism•Conservatism•Religiosity•Teaching quality•College qualityUnobservedfactorMeasure 1Measure 2Measure n. . .b1b2bne1e2e3PolyarchyFairness ofelectionsMeaningfulnessof electionsFreedom of expressionb1b2b4e1e2e3Unbiased reporting ofofficial
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