O slideshow foi denunciado.
Utilizamos seu perfil e dados de atividades no LinkedIn para personalizar e exibir anúncios mais relevantes. Altere suas preferências de anúncios quando desejar.

Ch04 General Issues in Research Design

Maxfield, Michael G. & Babbie, Earl R. (2011). Research Methods for Criminal Justice and Criminology, 6th Edition. Belmont, CA: Wadsworth Publishing.

  • Entre para ver os comentários

Ch04 General Issues in Research Design

  1. 1. 1General Issues inResearch Design
  2. 2. OUTLINE Introduction Causation in the Social Science Validity and Causal Inference Units of Analysis The Time Dimension How to Design a Research Project The Research Proposal
  3. 3. 3•Causation, units, and time are key elements inplanning a research study•As social scientists, we seek to explain the causesof some phenomenon (e.g., crime)•Often, criminal justice researchers want to find outsomething that involves questions of cause andeffect
  4. 4. 4•Causation is the focus of explanatory research•Cause in social science is inherentlyprobabilistic •Certain factors make crime/delinquency more or less likely within groups of people •Two models of explanation •Ideographic – Lists the many, perhaps unique considerations behind an action •Nomothetic – Lists the most important (and fewest) considerations/variables that best explain general patterns of cause and effect
  5. 5. 5•Assessing an idiographic explanation – positedby Maxwell (2005) •How credible and believable it is •Whether alternative explanations (“rival hypotheses) were seriously considered and found wanting•Assessing a nomothetic explanation – posited byShadish, Cook, & Campbell (2002) •Empirical relationship between variables •Temporal order (cause precedes effect) •No alternative explanations – no spurious other variable(s) affecting the initial relationship•Any relationship that satisfies all these criteria iscausal
  6. 6. 6•Within the probabilistic model, two types: •Necessary cause – Represents a condition that must be present for the effect to occur (being charged before being convicted) •Sufficient cause – Represents a condition that, if it is present, will pretty much guarantee that the effect will occur (pleading guilty before being convicted)
  7. 7. 7•Scientists assess the truth of statementsabout cause by considering threats to validity.•When we make a cause-and-effect statement,we are concerned with its validity – whether itis true and valid•Certain threats to the validity of our inferenceexist•These are reasons why we might be incorrectin stating that some cause produces someeffect
  8. 8. 8•Refers to our ability to determine whether achange in the suspected cause is statisticallyassociated with a change in the suspectedeffect•Are two variables related to each other?•Researchers cannot have much confidence instatements about cause if their findings arebased on a small number of cases
  9. 9. 9•An observed association between twovariables has internal validity if the relationshipis, in fact, causal and not due to the effects ofone or more other variables•Generally due to non-random or systemicerror•The threat to IV results when the relationshipbetween two variables arises from the effect ofsome third variable •Example: drug users sentenced to probation over prison recidivate less
  10. 10. 10•Concerned with whether research findings inone study can be replicated in another study,often under different conditions•Do the findings apply equally in differentsettings (locales, cities, populations)?•Kansas City evaluation found sharp reductionsin gun-related crimes in hot spots that hadbeen targeted for focused police patrols •Indianapolis and Pittsburgh launched similar projects
  11. 11. 11•Concerned with how well an observedrelationship between variables represents thecausal process•Refers to generalizing from what we observeand measure to the real-world things in whichwe are interested •e.g., close supervision of officers  more tickets? •e.g., Kansas City Preventive Patrol Experiment, “police visibility”
  12. 12. 12•The four types of validity threats can begrouped into these two categories•Bias – Internal Validity and StatisticalConclusion Validity threats are related tosystematic and nonsystematic bias•Generalizability – Construct Validity andExternal Validity are concerned withgeneralization to real-world behaviors andconditions
  13. 13. 13•Temporal order: which comes first?•A statistical relationship exists, but underlyingcauses affect both drug use and crime(Internal Validity threat)•What constitutes drug use? Crime?(Construct Validity threat)•How will policy affect drug use and crime? •A crackdown on all drugs among all populations will do little to reduce serious crime
  14. 14. •Bridges idiographic and nomotheticapproaches to explanation by seeking tounderstand how causal mechanisms operate inspecific contexts •Studies how such influences are involved in cause-and-effect relationships •Exhibits both ideographic & nomothetic approaches to explanation •"Can the design of streets and intersections be modified to make it more difficult for street drug markets to operate?"
  15. 15. 15•What or who is studied •Individuals - Police, victims, defendants, inmates, gang members, burglars, etc. •Groups - Multiple persons with same characteristics (gangs, cities, counties, etc.) •Organizations - Formal groups with established leaders and rules (prisons, police departments, courtrooms, drug treatment facilities, etc.) •Social artifacts - Products of social beings and their behavior (stories in newspapers, posts on the Internet, photographs of crime scenes, incident reports, police/citizen interactions)
  16. 16. 16•Ecological fallacy - Danger of makingassertions about individuals based on theexamination of groups or aggregations •Poor areas = more crime, therefore poor people commit more crime•Individual fallacy – Using anecdotal evidence tomake an argument •O.J. Simpson court resources•Reductionism - Failing to see the myriad ofpossible factors causing the situation beingstudied
  17. 17. 17•Time sequence is critical in determiningcausation•Time is also involved in the generalizability ofresearch findings•Observations can either be made more or lessat one point, or stretched over a longer period •Observations made at more than one time point can look forward or backward
  18. 18. 18•Observing a single point in time (cross-section)•Simple and least costly way to conductresearch•Typically descriptive or exploratory in nature•A single wave of the National CrimeVictimization Survey (NCVS) is a descriptivecross-sectional study that estimates how manypeople have been victims of crime in a giventime
  19. 19. 19•Permit observations over time •Trend – Those that study changes within some general population over time (UCR) •Cohort – Examine more specific populations as they change over time (Wolfgang study) •Panel – Similar to trend or cohort, but the same set of people is interviewed on two or more occasions (NCVS) (panel attrition)
  20. 20. 20•Gun ownership and violence study by Swissresearcher Martin Killias (1993) •Compared rates of gun ownership as reported in an international crime survey to rates of homicide and suicide committed with guns•May be possible to draw approximateconclusions about processes that take placeover time, even when only CS data is available•When time order of variables is clear, logicalinferences can be made about processes takingplace over time
  21. 21. 21•Asks people to recall their past for the purposeof approximating observations over time•People have faulty memories; people lie•Analysis of past records also suffer fromproblems – records may be unavailable,incomplete, or inaccurate•Prospective research – longitudinal study thatfollows subjects forward in time (Widom – childabuse/drug use)
  22. 22. 22•Cross-sectional study = snapshot – an imageat one point in time•Trend study = slide show – a series ofsnapshots in sequence over time, allows us totell how some indicator varies over time•Panel study = motion picture – givesinformation about individual observations overtime
  23. 23. 23•Designing research requires planning severalstages, but the stages do not always occur inthe same sequence•Beginning points for a line of research •e.g., interests, ideas, theories, new programs •Why does something occur? •Why is this how it is? •What about this possible program? •These questions may lead to others you might like to explore
  24. 24. 24•Find out what research has been done•Read newspaper stories, journal articles, checkout the Internet, talk to relevant people•Figure out your objective & intended audience•Generally, your purpose for undertakingresearch can be expressed in a report •You should be clear about the kinds of statements you will want to make when the research is complete
  25. 25. 25•Specify what you mean by the term in yourresearch - this doesnt necessarily mean youhave to settle for a single definition•What do you mean by the concept beingstudied?•If you are going to study fear of violent crime: •What is considered “violent crime”? •What is considered “fear”?•You need to specify ALL the concepts you wishto study
  26. 26. 26•A variety are available, each has strengths andweaknesses, choose one after considering thespecific concept you want to study •Interviews, surveys, field research, content analysis, official records •The best studies utilize more than one research method
  27. 27. 27•Create concrete ways of actually measuringyour concept•Fear and violent crime: •Questionnaire item: how safe do you feel in your house, downtown at night, etc. •Official records of violent crime incidents in that neighborhood, downtown, etc.
  28. 28. 28•Exactly who or what will you study?•Population – Group (e.g., of people) aboutwhom we want to be able to draw conclusions•Since it is generally unfeasible to study ALLmembers of that population, how will you take arepresentative sample?•Fear and violent crime: Will you includeelderly? Teenagers and kids? A particular race orgender?
  29. 29. 29•Collect the empirical data•Make the observations that you will process,analyze, interpret, apply, and review
  30. 30. 30•You have amassed a volume of observations ina form that usually is not easily interpretable•How will you make sense of the observations?•Code the data somehow
  31. 31. 31•Manipulate the data•Goal is to draw conclusions that reflect on theinterests, ideas, and theories which initiated ourresearch project•Calculate percentages of those who have beenvictimized by violent crime, those who fearviolent crime, differences among populationsubsets, etc.
  32. 32. 32•Utilize the research you’ve conducted and theconclusions you’ve reached•Make your findings known to others•Develop policy to address your findings•Determine what mistakes were made thatcould be corrected in the future•Determine how your research might feed intofuture research
  33. 33. 33•Begin by assessing: •Your interests •Your abilities •The resources available to you•What are you interested in studying? •What information is needed & how to obtain it •Review prior research in journals, books and governmental reports •“Triangulation”
  34. 34. 34•Problem/Objective •Data Collection Methods•Literature Review •Analysis•Research Questions •References•Subjects for Study •Schedule•Measurement •Budget