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Agenda: Research DesignAgenda: Research Design
Experimental
Non-experimental
Quasi-experimental
Quantitative and Qualitative research
ExampleExample
Objective: To find out the impact of sunshine on plants’ growth.
Treatment
Experimental Control
I.V.I.V.
Experimental designExperimental design
Sample: low birth weight infants that were in intensive care & their moms, from same hospital
Randomly assigned to treatment or control group Treatment: Training program to help them cope
w/ special needs of low birth wt infant I.V. Level 1 -- training. Level 2 -- no training D.V. Mom’s self-confidence, perception of
infant’s temperament, satisfaction w being mom
Experimental ResearchExperimental Research
Researchers manipulate independent variable - 2 levels
And measure the other (dependent variable) Give treatment to participants and observe if it
causes changes in behavior
Compare experimental group (w/ treatment) with a control group (no treatment)
Can say IV caused change in the DV
Experimental research designExperimental research design
Measure dependent variable Control extraneous variables
Hold constant The only difference between experimental
group and control group is the manipulated variable.
Treat groups equally except for treatment.
Randomize effects across treatments Design to eliminate alternative explanations
Random Assignment
A way to assign participants in your sample to the various treatment conditions (groups that will receive different level of the IV)
Any member of your sample has equal chance of being assigned in any treatment group
Quasi-experimental researchQuasi-experimental research
Naturally occurring conditions (IV change) No control over variables influencing
behavior (confounding variables) Another variable that changed along with the
variable of interest may have caused the observed effect
Variables that affect decision to offer helpVariables that affect decision to offer help
Field experiment - Philadelphia subway Hypoth: Person’s assessment of “cost” of helping
affected decision to help IV Perceived costs to helper were manipulated 1 - confederate fell down in subway car (no blood) 2 - confederate fell down in subway car and bit on
vial of theatrical blood (bloody) DV - Researcher measured the time it took before
someone helped Finding: help given faster when victim ________
Field experiment Field experiment - nursing home residents - nursing home residents
Independent variable: Degree of control over decisions that affect their lives
Group 1: were given responsibility/ control for making choices about home’s operation
Group 2: the staff would be responsible for their care and needs
Dependent variables: Activity level, happiness, physical health
Program evaluationProgram evaluation
Research on programs that are proposed and implemented to achieve
some positive effect on a group of individuals Outcome evaluation
Did the program result in the positive outcome for which it was designed?
Process evaluation Is program reaching target population, and
attracting enough clients? Is staff providing the planned services?
Non-equivalent control group Non-equivalent control group pre-test -- post-test pre-test -- post-test designdesign
Dependent Dependent
Variable Variable
Pre-test Post-test
Group 1 Measure Treatment Measure
Grp. 2 Measure No Treatment Measure Control
Research DesignResearch Design
Between subjects / independent groups Compare 2 separate groups
Within subjects / repeated measures Same participants experience both levels of IV
First IV level 1, followed by measure of DV. Then IV level 2, followed by measure of DV
Number of observations Timing of treatment (pre, post)
Key factors in research designKey factors in research design
Manipulate variable / Treatment Control of variables Control or comparison groups Assignment of groups to “treatment
conditions” Quantitative or Qualitative
Why use non-experimental Why use non-experimental correlational researchcorrelational research
Gathering data in early stages of research
Inability to manipulate variables
How naturally occurring variables relate in “real world”
Non-experimentalNon-experimental Correlational research Correlational research
Determine whether 2 or more variables are associated,
If so, to establish direction and strength of relationships
Observe variables as they are, can’t manipulate them
Correlational researchCorrelational research Interested in
Variable: # of gifts bought by college students Variable: time of semester -- early, middle, or late
Finding: Students more likely to purchase gifts at end of semester. These 2 variables are related.
Does end of semester cause more gift buying? Could be a 3rd variable (not measured) causing
the effect. If this is Fall semester project, what is likely the
3rd variable?
Causal - (Experimental) one variable directly or indirectly influences
another.
Correlational - (Non-experimental) Changes in one variable accompany
changes in another. A relationship exists. Don’t know if either
variable actually influences the other.
Non-Experimental ResearchNon-Experimental Research Researchers observe participants in
natural settings and describe them
Non-experimental Correlational
Experimental Causal Comparative
Descriptive
High LowCausality
Research designResearch design
Manipulate IV Random Assignment
Experimental (Causal) x x Quasi-experimental x
Non-experimental / Correlational
Predictive Descriptive
Experimental vs. Non-ExperimentalExperimental vs. Non-ExperimentalExperimental Non-
Experimental
Control?High Low
Causality?Strong Weak
Describe Reality?
Weak Strong
ApproachDeductive Inductive
Quantitative vs. Qualitative Quantitative vs. Qualitative ResearchResearch
Quantitative Research presents the results as quantities and numbers (i.e., statistics)
Qualitative Research presents results in words (e.g., quotations, descriptions)
Quantitative vs. QualitativeQuantitative vs. Qualitative
Quantitative Qualitative
Survey
Closed-end Open-end
Interviews
Structured Unstructured
Case Study
Field Work
Quantitative vs. QualitativeQuantitative vs. Qualitative
Quantitative Qualitative
Generalizablity?High Low
Flexibility?Low High
Systematic?Strong Weak
In-Depth?Weak Strong
ApproachDeductive Inductive
Select Select Quantitative or QualitativeQuantitative or Qualitative
Based on… The purpose of research or Research question
What’s already known about the topic The level of sensitivity (topic or participant) Availability of participants Availability of resources (time & budget) Needs of the audience
Homework 3) Homework 3) Literature review: Summary Literature review: Summary of two articles (Part I)of two articles (Part I)
Due: Feb. 4 (Feb. 6 is OK) Each student - write short summary of 2
scholarly journal articles about a research study)
This info will be used to develop intro section of your research proposal.
(See page 260 of Cozby). Each group member should use different
articles.
Each summary should includeEach summary should include Summarize main message, key
information or finding, or recommendation from the article
(a few sentences to 2 paragraphs) . Describe how this info justifies the
importance of your project
(a few sentences to 2 paragraphs) and/or Describe how this article helps you
develop research hypotheses, measures, or procedures for your group project.
Reflect about the article...Reflect about the article...
What was important for you about the article?
How does it relate to your project?
How might it help you improve your research?
What might you do differently if you were going to repeat that research?
Part II: Part II: Practice evaluating literaturePractice evaluating literature
For both articles, write (or summarize if long) 1) the study’s research questions, 2) hypotheses, 3) the problems that their research study
addresses. 4) Describe how the authors justified the need
and importance of their study. Find the above in the introduction section of
the article. Attach your articles to the assignment.
Introduction section of articleIntroduction section of article
Purpose of study and research question(s) Problems related to study topic Literature review Rationale (justification) for the study Hypotheses
Citation - APA StyleCitation - APA Style
Jones (1999) said blah, blah blah. Blah, blah, blah blah, blah, blah (Jones,
1999). Jones, Higa, and Vasquez (2000) said blah,
blah, blah. Blah, blah, blah blah, blah, blah (Jones,
Higa, & Vasquez, 2000). Blah, blah, blah (Smith as cited by Jones,
1999)
Conceptualization Conceptualization Operationalization Operationalization
Idea
Conceptualization
Operationalization
Clarificatio
n
What do I mean by ____?
How will I measure ___?
Measurable & Observable
OperationalizationOperationalization
Re-define a variable in terms of steps to measure
What the researcher must do to measure it
ExamplesExamples
Conceptual Definition Operational Definition
Amount of Sunshine The number of hours exposed to sun
Growth of Plant Daily growth of plants in height
Happiness Choice from “Very happy – Happy – Neutral – Unhappy – Very Unhappy”
Operationalizing:Operationalizing:Easy-going Easy-going (multi-dimensional)(multi-dimensional)
Looking for easy-going roommate
What could you do to screen if potential roommate would be “easy going?”
What would you specifically measure to determine “easy going?”
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