researcher psych #2

  1. 4 ways threats to validity
    -presence of confounding variables

    -unrepresentative samples

    -inappropriate statistical tests or violations of statistics assumptions

    -subject and experiementer effects

    *all these can be controlled
  2. (general control procedures) preparation of the setting
    -free of distractions that might interfere

    • -a natural setting increases external validity
    • *classroom setting
  3. (general control procedures) response measurement
    -use reliable and valid measures
  4. (general control procedures) replication
    • demontrates that findings are consistent adn robust
    • *someone can repeat the experiemtn
  5. (subject and experimenter effects) blind procedures
    best control for expetancy effects
  6. (subject and experimenter effects) single blind study
    pariticipant does not know what condition he or she is in
  7. (subject and experimenter effects) double blind study
    neither the experimenter or subject know what condition the participant is under
  8. (subject and experimenter effects) automation
    -reduces contact between participants and the experimenter

    • - gives the experimenter less oppurtunity to affect participants
    • *instructions may be on computer
  9. (subject and experimenter effects) using objective measures
    -objective measure require less judgement

    -provides less opportunity for subtle experimenter biases to affect the data

    • *ex) # of times kid punches someone instead of rating ona ┬áscale his aggresiveness
    • **less judgement less biases
  10. (subject and experimenter effects) multiple observers
    -reduces bias because it challenges observers to be as objective as possible

  11. (subject and experimenter effects) Using deception
    -hides purpose of the study from participants

    -need to weigh costs and benefits to use deception

    ex)milgram experiement
  12. PArticipant selection
    • -better able to generalize if your sample is representative
    • *target population
  13. (participant selection) target population
    those particiapnts you are interested in
  14. (participant selection) Accessible population
    portion of target population that is available to the researcher
  15. (participant selection) sample
    subset of the population on which measures are taken
  16. 3 different types of sampling procedures

    -stratified random sampling

    -ad hoc samples
  17. (sampling procedures) random sampling
    every participant has an equal chance of being sampled
  18. (sampling selection) stratified random sampling
    random sampling within strata (subgroups)

    *ususally in research or media
  19. (sampling selection) ad hoc samples
    -random sample from accesible population

    -must generalize cautiosly

    • -should describe sample to help define limits of generalizaiton
    • *most frequently used in psych research
  20. (participant assignemtns) free random assignment
    -random assignment of participation to groups
  21. (participant assignemtns) mathced random assignments
    -random assignments of participants in matched sets to groups
  22. (participant assignemtns) other mathcing procedures
    • match grops on key characteristics
    • *not a random assignemtn
  23. Key elements of true experiments
    -one or more control groups

    -random assingment of participants to groups
Card Set
researcher psych #2
controls to reduce threats to validity