Psbe2 08 research methods 2011-2012 - week 4
-
Upload
vlady-fckfb -
Category
Technology
-
view
119 -
download
0
Transcript of Psbe2 08 research methods 2011-2012 - week 4
Reliability
The consistency or repeatability of the measurements
The degree of accuracy to which a study reflects or assesses the specific concept that the
researcher is attempting to measure
4
Validity
Stability and Equivalence
• Test-retest reliability• Alternate-form reliability• Internal-consistency reliability
6time
Version1
Version1
Version2
Version2
Reliability
Equivalence
Internal Consistency
How related are individual items within the measure?
• Spearman-Brown• Kuder and Richardson Formula 20 (KR20)• Cronbach’s alpha
7
Replication in Research
• What do we mean by ‘replication’?
• Three factors to consider:– When– How is the replication is conducted?– By whom
8
Replication in Research
• What do we mean by ‘replication’?
• Three factors to consider:– When– How is the replication is conducted?– By whom
Early replications are more valuable than later ones
9
Replication in Research
• What do we mean by ‘replication’?
• Three factors to consider:– When– How is the replication is conducted?– By whom
The difference between precise and varied replication
10
Replication in Research
• What do we mean by ‘replication’?
• Three factors to consider:– When– How is the replication is conducted?– By whom
Independence of replicators
11
Validity
• Content-related– How well a measure represents all dimensions
• Criterion-related– Concurrent vs. predictive validity
• Construct-related– Convergent vs. discriminant validity
12
Observational Methods
• Categories based on intervention by researcher– Observation without Intervention– Observation with Intervention
• Categories based on methods for recording behavior– comprehensive record– selected behaviors
Observation without Intervention
• Naturalistic Observation– observation in natural (real-world) setting without
attempt to intervene or change situation– use when ethical considerations prevent
experimental manipulation• Goals– describe “normal” behavior, examine relationships
among naturally occurring variables– establish external validity of lab findings
Observation with Intervention
• Most psychological research involves intervention
• Three methods in natural settings– participant observation– structured observation– field experiment
Observation with Intervention
• Participant observation– observer is active participant in the natural setting
he or she observes• undisguised: people know they’re being observed
(e.g., Kitchen Stories, 2003 Norwegian film)• disguised: people don’t know they’re being observed
Observation with Intervention
• Problems with participant observation– Reactivity• when people change their usual behavior because
they’re being observed• disguised participant observation controls reactivity
– Observers lose objectivity or become too involved in situation
– Observers influence behavior of people they’re observing (e.g., Hawthorne Effect)
Observation with Intervention
• Structured observation– set up (structure) specific situation in order to
observe behavior– used when behavior is difficult to observe as it
naturally occurs– researchers use confederates to structure
situations– problems: when observers don’t follow same
procedures across observations
Observation with Intervention
• Example of structured observation– Simons and Levin (1998): “change blindness”
http://www.youtube.com/watch?v=FWSxSQsspiQ
Observation with Intervention
• Field Experiment– manipulate independent variable in natural setting
and observe behavior (dependent variable)• two or more conditions to compare (IV)• often use confederates to create conditions• strive for control in natural setting
On Being Sane in Insane Places
Original Article:http://cooley.libarts.wsu.edu/soc3611/Documents/Being_Sane_in_Insane_Places.pdf
Video:http://www.youtube.com/watch?v=Kq-7uvVOoyk
In Fiction:Simpson’s Episode S03E01 – “Stark Raving Dad“
22
Dr. David Rosenhan
Maximising Serendipity
• With– Common sense– Hard work– The right info
– And a bit of luck
23
Raising the flag on Iwo Jima - 1945
Errors in Observational Research
• Non-interactional artifacts– Interpreter biases– Observer biases
• Interactional artifacts
24
Non-reactive Measures
• Archival research
• Physical Traces
• Unobtrusive Observation– Simple– Contrived
25
Selecting Judges
• Identify the type of judge that is most likely to produce accurate judgments
– Search the literature– Test them
26
Rating Biases
• Errors of Leniency– e.g., Halo Effect
• Severity Errors• Errors of Central Tendency• Logical Errors
27