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