Hawthorne Effect: 'The Attention Effect"
Participants perform better when they are being observed and when the light was increased
to get rid of: experimental group with and one without attention
Three Groups Used for Controlling Hawthorne effect
1. Experimental Group
2. Control Group with Attention
3. Control Group without Attention
A source of confusion regarding an explanation for a treatment; makes it difficult to explain, a situation where the effect of one variable on the response variable cannot be separated from the effect of another variable on the response variable.
Double Blind Experiment
an experiment in which neither the experimenter nor the participants know which participants received which treatment
a standard series of ambiguous stimuli designed to elicit unique responses that reveal inner aspects of an individual's personality
the difference between a sample's results and the true result if the entire population had been interviewed
Errors due to bias; this type of error is not reduced by increasing the sample size
non-probability design in which you handpick subjects on the basis of personal judgment about their representativeness.
selection of participants through referrals from earlier participants; also called network sampling
the population is divided into subpopulations (strata) and random samples are taken of each stratum
giving participants in a research study a complete explanation of the study after the study is completed
The extent to which a test seems on its surface to be measuring what it purports to measure
the characteristic of an experiment that allows one to draw accurate inferences about the causal relationship between an independent and dependent variable
the extent to which a test samples the behavior that is of interest (such as a driving test that samples driving tasks).
A group of research participants selected from a population each of whose members did not have an equal chance of being chosen
A sample is this if every individual in the population has an equal chance of being selected
an experiment in which potentially confounding variables are satisfactorily controlled, usually by (a) random assignment of participants to experimental conditions or (b) sequencing of experimental conditions
Extent to which a selection device measures the theoretical construct or trait (e.g., intelligence or mechanical comprehension).
A group interview technique that obtains data through discussion between research participants in a group setting.
Advantages of Focus Groups
• Advantages: relatively inexpensive, giving researcher immediate feedback, they raise issues that merit further studies, test clarity and fairness or survey questions
Disadvantages of Focus Groups
-Ease of understanding may make it too compelling
-Participants recruited may not be typical
-Setting may make participants uncomfortable
-Some participants may dominate the conversation
Threats to internal validity
1) maturation of subjects (psychological and physical changes), 2) mortality (subjects withdrawing), 3) instruments used to measure the bx or trait, 4) statistical regression (high or low scores move toward mean if measure used again)
dividing a population into subgroups (clusters) and forming a sample by randomly selecting clusters and including all individuals or objects in the selected clusters in the sample
revealing intimate aspects of oneself to others
When a researcher uses multiple sources for collecting data (ie. multiple intervews with different people, all the people are different sources)
When a researcher uses multiple methods for collecting data (ie. interview, survey, observations)
When multiple researchers are used to collect data
a research method in which investigators systematically observe people while joining them in their routine activities
when similar measurements are obtained by different observers rating the same persons, events, or places- studies are said to have greater reliability
Use of groups that are not assigned at random (example: grouped by convenience)
O_ _ _ X_ _ _ O_ _ _
1. Strong possibility that groups are not initially the
2. Selection - History Interaction: because they were
not chosen randomly, they may be systematically
subjected to different life experiences.
3. Selection - Maturation Interaction: Two groups
may have been at different developmental stages
during the pretest, which would have led to
different rates of maturation.
4. Mortality: Differential loss of participants from the
groups tho be compared
Pre Post Randomized Design
Group 1 is randomized, pretested, given treatment, and then posted tested. Group 2 is randomized, pretested, given no therapy, and then post tested., a-two groups
b-one group gets treatment, both get pretest
a) The silent probe- best way to encourage someone to elaborate is by not saying nothing at all
b) Overt encouragement- simple ways to directly encourage response but not play into the interviews bias... Okay and uh huh is sufficient enough
c) Elaboration- By asking for more info
d) Ask for clarification
Pictorial (thematic apperception test (TAT), Rorschah Test, projective cartoon), verbal (word association, sentence completion), expressive (playing with dolls, drawing, painting, role playing).
Qualitative v. Quantitative
If you are observing and writing descriptions of the behavior of a group of people, that is qualitative. If you are looking at the frequencies of certain types of behavior, that is quantitative.Basically, you can think of qualitative data as words, and quantitative data as numbers.
John Henry Effect
People in ontrol group come to know about their inferior status and try to outperform those in experimental group. (get rid of : try to hide information from participant)
try to give similar treatments to both groups; one group will be given actual cancer medication, other will be given sugar pill
Participant triest to please ou by giving a certain answer (try to hide expectations)
Advantages of Projective Techniques
provides rich data reduces social desirablity
Highly trained researcher are required to interpret the results, can be expensive, time consuming, non numerical results based on interpreters ideas, participants do not necessarily represent the greater population
Types of Projective techniques
Word Association: A word is given and participant is asked to respond.
Expression Technique: Participant is asked to express the feeling or attitude of other people (ie: mimic Charlie Chaplin).
Completion Test: Participant is asked to complete a sentence of a story.
Construct Test: Write about a picture.
Inkblot Test: Shown an abstract inkblot and asked what they see; the participant projects a certain image, feeling, or idea about the inkblot.
1 reviewing the purpose of the study
2 reviewing the procedures used
offering to share results with participants when they become available
How to improve content validity
Avoid using ambiguous words
Consider educational levels of participants
Questions should convey the same meaning to all the participants
PRetest posttest randomized control group design
Group 1 is randomized, pretested, given treatment, and then posted tested. Group 2 is randomized, pretested, given no therapy, and then post tested.
Randomization creates comparability
Advantage of using a pretest is that it permits researchers to determine how much each group has gained, not just whether they are different at the end of the experiment
However, sometimes having a pretest causes a problem because it can sensitize participants to the experimental treatment and, in effect, become part of the treatment.
Posttest only randomized control group design
An experiment without a pretest
Reduces pretest-sensitization caused by the Pre,Post Test
Randomization creates comparability
Solomon Randomized Four Group Design
"The Best of Both Designs" combination of designs A and B
Has four groups
Advantage: researchers can compare the first two groups to determine how much gain is achieved and can also compare the last two groups to determine whether the treatment is more effective than the control condition in the absence of a pretest (without pretest sensitization)
Disadvantage: a researcher must begin with a reasonably large pool of participants so that when they are divided into four groups, each of the groups will have a sufficient number to yield reliable results.
One Group Pretest Posttest Design
Researcher pretests, treats, and then posttests one group of participants
Disadvantages: (possible internal validity)
History- other environmental influences on the participants between the pretest and the posttest
Maturation- participants became older, wiser, or smarter
Instrumentation- possible changes in measurement procedure from the time it was used as a pretest to the time it was used as a posttest
Testing- effects of the pretest on the performance exhibited on the posttest
Statistical Regression- occurs only if participants are selected on the basis of their extreme scores.
The interpretation of pretest to posttest change is confounded by multiple explanations
One Shot Case Study
one group is given a treatment followed by a test
For instructional purposes (ie. a teacher provides instruction on a unit of material and follows it with an achievement test)
Cannot know causation, because the design fails to make comparisons
Static Group Comparison Design
Nonequivalent Control Group Design
Researchers use two comparison groups that are not formed at random
Selection- Very strong possibility that the two groups are not initially the same in all respects
They may be systematically subjected to different life experiences
Selection- maturation interactions-- perhaps the two groups, on average, were at somewat different developmental stages at the time of pretest, which would have led to different rates of maturation in the two groups, which could affect self-concept
Mortality- diffferential loss of participants from the groups to be compared
Researchers often use some form of matching to increase the internal validity of the results; however there can still be a danger that the two groups may not have been matched on all relavant variables