Research Design Blue 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 plan Highlights 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

Reference Period Retrospective - Prospective Prospective Retrospective

Nature of Investigation Semi-experimentalNon-experimental Experimental

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 PERIOD TIME 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 Intervention 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 