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Measurement

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Measurement

  1. 1. Measurement <ul><li>Andrew Martin -- PS 372 </li></ul>
  2. 2. What is measurement? <ul><li>Measurement is the process by which phenomena are observed systematically and represented by scores and numerals. </li></ul>
  3. 3. Operationalization <ul><li>Political scientists have figure out how to measure the presence of absence of concepts in the real world. </li></ul><ul><li>The process requires political scientists to provide an operational definition of their concepts. Sometimes this is called operationalization . </li></ul>
  4. 4. © Judith A. Perrolle 1987
  5. 5. Operationalization Examples <ul><li>Concept: Fundraising </li></ul><ul><li>Operational definition: Itemized receipts of daily campaign contributions made to each presidential candidate (FEC Database) (Haynes, Crespin, Zorn (2004) )‏ </li></ul>
  6. 6. Operationalization Examples <ul><li>Concept: legislator ideology </li></ul><ul><li>Operational definition: Legislator ratings from Americans for Democratic Action, which is set on a 100-point scale, 0 being “most conservative” and 100 “most liberal.” </li></ul>
  7. 7. What about corruption? <ul><li>How would one operationalize corruption? </li></ul>
  8. 8. Political Corruption <ul><li>Most define political corruption as the use of legislated powers by government officials for illegitimate private gain. </li></ul><ul><li>However, if one were going to going to operationalize political corruption, how would it be measured? </li></ul>
  9. 9. Transparency Int'l <ul><li>Transparency International is a non-governmental organization that tracks corruption in the public sector around the globe. </li></ul><ul><li>The Corruption Perceptions Index (CPI) focuses on corruption in the public sector. </li></ul>
  10. 10. Corruption Perceptions Index <ul><li>The surveys used in compiling the CPI ask questions relating to the abuse of public power for private benefit. </li></ul><ul><li>These include questions on: </li></ul><ul><ul><li>bribery of public officials </li></ul></ul><ul><ul><li>kickbacks in public procurement </li></ul></ul><ul><ul><li>embezzlement of public funds </li></ul></ul><ul><ul><li>strength and effectiveness of public sector anti-corruption efforts </li></ul></ul>
  11. 12. Corruption Perceptions Index <ul><li>Measures the perceived levels of public sector corruption in 180 countries and territories. </li></ul><ul><li>A composite index based on 13 different expert and business surveys. </li></ul><ul><li>Is not intended to measure a country's progress over time. </li></ul>
  12. 13. U.S. Corruption? <ul><li>U.S. DOJ Public Integrity section tracks data on the number of federal, state and local government officials prosecuted and convicted for corruption crimes. </li></ul><ul><li>The data the provide the number of people prosecuted by each U.S. Attorneys office. </li></ul><ul><li>Corruption isn't clearly defined, but cases include election fraud, obstructing an investigation and violation of campaign finance regulations. </li></ul>
  13. 14. Three-step process <ul><ul><ul><ul><ul><li>1. Abstract concept </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>2. Conceptual definition </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>3. Operational definition </li></ul></ul></ul></ul></ul>
  14. 15. Measurements <ul><li>The quality of measurements is judged with regard to both accuracy and precision. </li></ul><ul><li>Accuracy refers to how close the measure comes to explaining the true value of a concept. </li></ul><ul><li>Precision refers to the consistency of the measure in quantifying the concept. </li></ul>
  15. 17. Measurements <ul><li>Reliability is the extent to which an experiment, test or any measurement procedure yields the same results in repeated trials. </li></ul>
  16. 18. Testing Measurements <ul><li>Test-retest method -- Apply the same test to the same observations after a period of time has passed. </li></ul>
  17. 19. Testing Measures Alternative-form method -- Use two different measures of the same concept rather than the same measure. Ex: Using two different kinds of ideology measures for legislators. NOMINATE scores vs. Interest Group scores
  18. 20. Testing Measurements <ul><li>Split-halves method -- Using two different measures with both measures applied at the same time. </li></ul><ul><li>Ex: Nominate and IG scores both in the same statistical model </li></ul>
  19. 21. Measurements <ul><li>Validity -- the degree of correspondence between the measure and the concept it is thought to measure. </li></ul><ul><li>Examples of validity issues -- Native Americans on U.S. Census, racial politics research, election turnout and voting </li></ul>
  20. 22. Measurements <ul><li>Face validity is asserted by arguing that a measure corresponds closely to the concept it is designed to measure. </li></ul><ul><li>(Ex: Party ID and Ideology)‏ </li></ul>
  21. 23. Face Validity <ul><li>To confirm the validity of ideology and political party identification measures, I could examine their relationship: </li></ul>Political Party U.S. Senate U.S. House Republicans 20 16 Democrats 87 92 2007 ADA score based on a 100-point scale, with 0 meaning “always votes conservative” and 1 meaning “always votes liberal.” The measure is typically based on 20 voters in the 2008 congressional session. Senators of interest: Obama: 75 (15 votes 15/15) McCain: 10 (15 votes 2/15)‏
  22. 24. Measurements <ul><li>‏ </li></ul><ul><li>Content validity is demonstrated by ensuring that the full domain of a concept is measured. </li></ul>
  23. 25. Content Validity <ul><li>Example: Dahl’s polyarchy </li></ul><ul><li>Polyarchy , according to Dahl, is a form of representative democracy characterized by a particular set of political institutions. These include elected officials, free and fair elections, inclusive suffrage, the right to run for office, freedom of expression , alternative information and associational autonomy. </li></ul>
  24. 26. Content Validity <ul><li>Domain: Dahl book </li></ul>
  25. 27. Measurements <ul><li>Construct validity is demonstrated for a measure by showing that it is related to the measure of another concept. </li></ul><ul><li>Ex: Ideological identification and level of education. </li></ul>
  26. 30. Inter-item Association <ul><li>Inter-item association relies on the similarity of outcomes of more than one measure of a concept to demonstrate the validity of the entire measurement scheme. </li></ul><ul><li>Ex: Candidate strength can be cross validated by comparing measures of campaign funds, polling numbers, primary votes and newspaper coverage. </li></ul>
  27. 31. Correlation <ul><li>A correlation indicates the direction and strength of a linear relationship between two random variables. </li></ul>

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