1. Chapter 6 STUDY DESIGN

2. Definition
Study design refers to the methodology that is used to investigate a particular phenomenon or a situation.
Is a plan that outlines how a research project will be conducted in order to get the most legitimate results from the study.
All study designs provide meaningful information when used appropriately and their strengths and limitations are understood.

3. Types of Study Design
There are different approaches to research, and different study designs are used to answer different questions. The following designs are discussed in this chapter:
Designs based on the number of contacts
Designs based on the reference period
Designs based on the nature of the investigation
Others

4. 1. Designs Based on the Number of Contacts
Cross-sectional study design
Before-and after study design
Longitudinal study design

5. i. Cross-sectional Design
Involves observations of a sample, or cross- section of a population or phenomenon that are made at one point in time.
In this design you decide what you want to find out, identify the study population, select a sample, and contact your respondents to find out the required information.

6. Examples :
a. The attitudes of students towards the facilities available in the library
b. The quality assurance of a service provided by an organization
c. The relationship between the home environment and the academic performance of student

7. ii. Before-and-after Design
Appropriate for measuring the impact or effectiveness of a program or services.
Examples:
The effect of advertisement on the sale of a product
The impact of increased funding on the quality of teaching in universities
The effectiveness of a marriage counseling on marital life.

8. Advantages & Disadvantages of Before and after Design
The main advantage is the ability to measure change in a phenomenon or to assess the impact of an intervention. Some of the disadvantages are:
Expensive & time consuming
Attrition(reduction) or changes in the study population.
Unable to ascertain whether independent or extraneous variables are responsible for bringing the change in the dependent variable.
Unable to quantify the contribution of independent and extraneous variables separately.

9. Maturation effect (e.g. young children)
Reactive effect of the instrument (e.g. impact of a program on participants awareness).
Regression effect(retreating) . This is in a situation where the participants change their attitude at the time of the post-test period.

10. iii. Longitudinal Study Design
Is a design that helps us to determine the pattern of change in relation to time.
Is useful when:
You wish to study a group of population adopting a program in relation to time
You need to collect factual information on a continuing basis
In longitudinal studies:
The study population is visited a number of times at regular interval.
The information gathered each time is identical.
Collected data may not be from the same respondents.

11. Advantages & Disadvantages of Longitudinal Study Design
The main advantage is that it allows the researcher to measure the pattern of change and obtain factual information, requiring collection on a regular or continuing basis. The design has the same disadvantages as before-and after design, in addition to: Conditioning effect: this is a situation where, if the same respondents are contacted frequently, they begin to know what is expected of them and may respond to questions without thought, or they may lose interest in the study.

12. 2. Study Designs Based on the Reference Period
1. Retrospective Studies
Investigate a phenomenon, situation, problem or issue that has happened in the past.
They are usually conducted either on the basis of the data available for that period or on the basis of respondents’ recall of the situation.
Examples:
The living conditions of original people in Australia in the early twentieth century.
The utilization of land before World War II in the U.A.E.
A historical analysis of migration in the U.S.

13. 2. Prospective Studies
Refers to the likely frequency of a phenomenon, situation, problem, attitude or outcome in the future.
Such studies attempt to establish the outcome of an event or what is likely to happen.
Examples:
To determine the impact of maternal and child health services on the level of infant mortality.
To establish the effects of a counseling service on marital problems.
To find out the effect of parental involvement on the level of academic achievement of their children.

14. 3. Retrospective-Prospective Studies
Focus on past trends in a phenomenon and relate it with the future.
Research study can be classified under this category if it measures the impact of an intervention without a control group.
Therefore before-and-after studies without control group will be classified as retrospective-prospective studies.
Examples:
1. The impact of incentives on the performance of workers.
2. The impact of maternal health services on the infant mortality rate.

15. 3. Study design based on the Nature of Investigation
Experimental Study: is a study where a researcher uses an experiment to investigate a relationship by starting from the cause to determine the effects.
Let us look at an objective of this study:
To find-out the relationship between watching violent movies and violent behavior among children
Violent Movies Violent Behavior
Cause (Starting point) Effect (Ending point)

16. Some issues to understand about Experimental Design:
1. Controlled or Natural Environment
An experimental study can be carried out in either a ‘controlled’ or a ‘natural’ environment.
In a controlled environment the study population is in a ‘controlled situation’ such as a laboratory or special room.
In the natural environment the study population is exposed to an intervention in its own environment.

17. 2. Randomization
Experimental studies can be further classified on the basis of whether or not the study population is randomly assigned to different treatment groups.
In a Random Design, the experimental group or the control group is not predetermined but randomly assigned.
This means each and every individual of a study population has an equal and independent chance of being assigned to an experimental or control group.

18. This is important in comparable designs in which we intend to compare two or more groups.
The process of randomization ensures that the groups are comparable in every aspect except the treatment.
In a Non-Random Design, the experimental group or the control group is predetermined, and no equal chance for the participants to be in an experimental or control group.

19. 4. Other Designs
Action research : Research is a means to action, either to improve your practice or to take action to deal with a problem or an issue
Feminist research : focuses on experiences and viewpoints of women; tries to reduce the power imbalance between men and women; and creates awareness of women’s issues and concerns, and to promote equality between gender.
Cross-over comparative experimental design: In this design the experimental group becomes control group and vice versa.
Replicated cross-sectional design: In this design you select participants at different phases of the program to form the basis of the study.
Trend studies: is to trace changes over a period of time. Enables you to find out what has happened in the past, what is happening now and what is likely to happen in the future.

20. Cohort studies : based on the common characteristic such as year of birth, graduation or marriage, within a subgroup of a population.
Panel studies : trend, cohort and panel studies are similar except that panel studies are longitudinal and prospective in nature and collect information from the same respondents. In the trend and cohort studies the information can be collected in a cross-sectional manner and the observation points can be retrospectively constructed.
Blind studies (Placebo design): The population does not know whether it is getting real or fake treatment.

21. Double-blind studies: Neither the researcher nor the participants know who is receiving real or fake treatment.
Case studies: Thorough analysis of individual case. The case may be a person, group, episode, process, community, society or any other unit of social life. The assumption of the approach is that the case being studied is typical of cases of a certain type so that, thorough intensive analysis, generalization may be made that will be applicable to other cases of the same type.

22. END Of CHAPTER 6