1 / 25

Introduction to Research Methods

Introduction to Research Methods. How we come to know about crime. Why Study Crime?. To learn about the causes of crime Make predictions about criminal behavior Provide information to policy makers. The Desire to Generalize. Goal: External Validity

jenny
Download Presentation

Introduction to Research Methods

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Introduction toResearch Methods How we come to know about crime

  2. Why Study Crime? • To learn about the causes of crime • Make predictions about criminal behavior • Provide information to policy makers

  3. The Desire to Generalize • Goal: External Validity • We seek knowledge that is generalizable to some larger group • Method: Random sampling • Yields a representative set of observations • Each member of the population has an equal chance of being measured

  4. Statistical Significance • A result is statistically significant if the probability that it is due to chance is less than 5% (α = .05), p < .05

  5. What Is a Variable? VariableAttributes/Values young, middle-aged, old male, female plumber, lawyer, professor Race Social Class

  6. Describing VariablesMeasures of Central tendency Mode = 16 13 Median = 15.5 13 Arithmetic Mean (Average) = (ΣYi)/N = 392/26 = 15.07

  7. Two Kinds of Variables • Dependent variable: what we wish to explain or understand (crime, violence) • Independent variable: what we think explains the dependent variable (poverty, age, associating with other criminals) Dependent Variable Independent variable

  8. Temporal Order Unemployment Property Crime Research Designs • Cross-Sectional: Gather data all at once • Longitudinal: Gather data over time to ensure proper causal ordering Property Crime Unemployment

  9. Measures of Association:Correlation • Do values on one variable correspond to values on another variable? • If no, correlation = 0 • If yes • Correlation = +1.0 • Correlation = -1.0

  10. Positive Correlation:Poverty and Homicide in Chicago Homicide Rate r = .51 Poverty

  11. Negative Correlation:Neighborhood Satisfaction and Poverty Neighborhood Satisfaction r = - .66 Poverty

  12. No Correlation:Social Ties and Poverty in Chicago Social Ties r = .02 Poverty

  13. Crosstabulation:Homicide by Poverty in Chicago Positive Relationship

  14. Neighborhood Satisfaction byPoverty in Chicago Negative Relationship

  15. Social Ties by Poverty in Chicago No Relationship

  16. WARNING:Correlation = Causation Ice Cream Murder Season Ice Cream Murder “Spuriousness”

  17. Criteria of Causality • Temporal order • Covariation • No plausible alternative explanation • Association between two variables is not the result of some other variable causing them both • The relationship between the independent and dependent is not spurious

  18. Drawing Causal Diagrams

  19. Data Gathering Methods • Survey Methods • Field Observation (ethnography) • Unobtrusive Measurement

  20. Gender Discriminationat XYZ University? XYZ University has 2 colleges: Liberal Arts and Engineering

  21. College of Liberal Arts

  22. College of Engineering

  23. Conclusion • There is no gender discrimination at XYZ! • Women tend to apply to departments that have higher rejection rates • Moral of story: control variables • Simpson’s paradox

  24. Experimental Research Design RANDOM ASSIGNMENT Experimental GroupControl Group Measure DV Measure DV Compare Test Remeasure DV Remeasure DV Compare

  25. The Scientific Study of Crime Theory Written explanation of why things happen Empirical Hypotheses Generalizations Observation Scientific methods for observing what happens

More Related