research design blue print for conducting a study april 21, 2014 rg 701- advance research methods
TRANSCRIPT
Research DesignBlue print for conducting a study
APRIL 21, 2014
RG 701- ADVANCE RESEARCH METHODS
What is Research Design?
A plan, structure and strategy of investigation so conceived as to
obtain answers to research question or problem.
Blueprint of research study Operationalizing the variables
Sample selection
Data collection
Analyzing results
‘How’ of the research journey
Once Research question has been finalized
◦ Research Problem: decided what you want to study
THEN
Need to determine how to conduct study
Need to design your research
◦ Set of instructions for researcher to gather and analyze data
◦ Scheme of plan of actions for meeting the objectives
Purpose To provide a plan in answering research question
Important Consideration:◦ To minimize the possible errors◦ To maximize the validity and reliability of data
In order to maximize the control over factors that could interfere with the validity of the findings
Functions of a Research Design
1. Conceptualize an operational plan to undertake the various procedures and tasks required to complete your study
2. Control of variance: Ensure that these procedures are adequate to obtain valid, objective and accurate answers to the research question
The researcher’s planHighlights the methods and tools that are used during research process
Name ‘study design’
Detailed information regarding:
◦ How the study will be conducted
◦ Study population
◦ Sample size
◦ Type of data that will be collected
◦ Identification of variables
◦ Data collection means/method
◦ Where interviews (if required) be conducted
◦ Managing Ethical issues
◦ Etc.
Reliability of Variables Consistency, stability, or dependability of data
A research method should yield the same result, even if conducted twice or more
Validity of variables Data need not only be reliable but valid as well
Validity refers to which extent an instrument is able to actually measure what it is supposed to measure
2. Theory of Causality Selection of a study design that will minimize the effects of
◦ extraneous variables influencing the independent variable
◦ chance or random error: due to random or chance variables –change in dependent variable due to respondent’s state of mode or ambiguity in the research instrument (ambiguous questions)
STUDY DESIGN IN QUANTITATIVE RESEARCH
Types of Research Design See Fig 8.1of text book
Classification based on:◦ Number of contacts◦ Reference period of study◦ Nature of the investigation
Number of Contacts
Three or moreTwoOne
X-sectional studies Before and after studies Longitudinal studies
Study Design
Reference Period
Retrospective - ProspectiveProspectiveRetrospective
Study Design
Nature of Investigation
Semi-experimentalNon-experimentalExperimental
Study Design
Study Based on
NUMBER OF CONTACTS
Cross-sectional Study Design
Simple in design
Also known as ‘one-shot’ or ‘status studies’
Best suited for finding out the prevalence of a phenomenon, situation, problem, attitude or issue
Takes one time cross-section of a population
Cross-sectional with regard to both◦ Study population◦ Time of investigation
Disadvantage:◦ Can not measure change
Before & After Studies Also known as ‘Pre-test/post-test’ design
Measures change
Can be described as two sets of cross-sectional data collection points on the same population in time
Change is measured by comparing the difference in the variable(s) before and after intervention
Disadvantages◦ Expensive and difficult◦ Measures total change including due to extraneous var.◦ Time lapse problems◦ Reactive effect of instrument◦ Regression effect
Longitudinal Studies Before and after only measures change but not the trend…
Longitudinal studies determine the pattern in change in relation to time
Intervals may vary from study to study
Considered as series of repetitive cross-sectional studies
Allows researcher to measure the pattern of change with enhanced accuracy
Disadvantages◦ Conditioning effect
Study Based on
REFERENCE PERIODTIME FRAME IN WHICH STUDY IS EXPLORING A PROBLEM
Retrospective Investigates a phenomenon, situation, problem or issue that has
happened in the past
conducted on the basis of:◦ data available for that period or ◦ respondents’ recall of the situation
Prospective
Refers to the likely prevalence of a phenomenon, situation, problem or outcome in the future
Establishes the outcome of an event or what is likely to happen
Researcher must wait for an intervention to register its effects
Retrospective -Prospective
Focuses on past trends in a phenomenon and study it into the future
Part of data is collected retrospectively from existing records before the intervention in introduce
Influence of intervention is studied afterwards
Study Based on
NATURE OF INVESTIGATION
Experimental
Starting from cause to establish its effects
Introducing the intervention and monitor the change
Flexibility of controlling or manipulating the independent variable
Some commonly used experimental study designs:
◦ Before-and-after
◦ Control group design
◦ Double control design
◦ Comparative design
Control group design Two population groups are selected for comparison (comparable in every
respect except for the intervention):
1. Experimental group◦ Receives/is exposed to the intervention
2. Control group◦ not exposed to the intervention
3. Chief objective of the control group is to quantify the impact of extraneous variables
4. Helps to ascertain the impact of the intervention only
Continu….Control group design
1. Make ‘Before’ observations on both groups (same time)
2. Experimental group is exposed to intervention
3. Make ‘after’ observations on both groups
4. Calculate difference in the ‘before’ and ‘after’ observations between the groups regarding dependent variable(s)
Study population
Study population Study population
Study populationIntervention
I/var.
Experimental Group
Control Group
D/var. Y’e D/var. Y”e
D/var. Y’c D/var. Y”c
Exp G: Total Change in D/var. Ye = (Y”e-Y’e) = impact of (intervention ± extraneous var. ± chance var.)
Cont. G: Total Change in D/var. Yc = (Y”c-Y’c) = impact of (extraneous var. ± chance var.)
Difference between Ex & Cont Groups equals to the ‘Impact of the Intervention’
Double Control Groups Two control groups
To quantify the impact due to the research instrument
Exclude one control group from ‘before’ observation
Comparative design
The study of the effectiveness of different interventions
The study population is divided into same number of groups as the number of interventions
Matched Control Experimental Design
Identical members from study population selected for study
Non-experimental
Starting from effects to trace the cause
effects/outcomes --------- causation
Observation of a phenomenon and then establishing its cause
Semi-experimental Has properties of both experimental and non-experimental studies
References Text book
http://www.slideshare.net/ludymae/chapter-7the-research-design