1. RESEARCH DESIGN Prof .A.Santham Lillypet Registrar (Acadamic )
Prof and HOD
Dept. of Community Health Nursing
MSRINER
Bangalore

2. DO YOU SEW ?
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3. THIS SESSION WE WILL DEAL WITH
MEANING
DEFINITION
PURPOSE
FUNCTION
TYPE OF STUDIES
CRITERIA FOR RESEARCH DESIGN
CLASSIFICATION OF RESEARCH DESIGN
ADVANTAGES AND DISADVANTAGES OF RESEARCH DESIGN

4. MEANING
The research design is the detailed plan of the investigation. In fact, it is the blue print of the detailed procedures of testing the hypotheses and analysing the obtained data.

5. DEFINITION
The sequence of those steps taken ahead of time to ensure that the relevant data will be collected in a way that permits objective analysis of the different hypotheses formulated with respect to the research problems.

6. PURPOSE
The purpose is to provide a maximum amount of information relevant to the problem under investigation at a minimum cost.

7. FUNCTIONS
It answers the research questions as objectively, validly and economically as it is possible.
It acts as a control mechanism. In other words, it enables the researcher to control unwanted variances.

8. CRITERIA OF RESEARCH DESIGN
There are three criteria’s
Capability to answer research questions adequately
Control of variable
Generalizability

9. VARIOUS TYPES OF STUDIES
Exploratory studies
Descriptive studies
Explanatory studies

10. TYPES OF DESIGN
Qualitative
Quantitative

11. TYPES OF DESIGNS – QUANTITATIVE
Type of design
Examples
Purpose
Experimental
True or Classic experiments
Pre test, post test control group design
Post test only control group design
Solomon four group design
To know in order, to predict changes, to explain
Quasi - experimental
Non equivalent control group design
Time series design
To know it order, to predict, explain.
Pre experimental
One short case study
One group pre-test – post test design
To describe to suggest limited prediction or explanation

12. Type of design
Examples
Purpose
Descriptive exploratory
Case study
Comparative study
Classification study
Concept formulation
To assemble new information to describe in order to know to analyse characteristic.
Survey
Interview
Questionnaire
To describe or Explain
Others
Methodological
Ex post facto
Correlational
To develop or evaluate methods
To describe, predict
To explain variation

13. Qualitative Research designs
Phenomenology
Ethnography
Grounded theory
Historical
Epidemiologic designs
Evaluative design
Methodological

14. SYMBOLIC PRESENTATION OF RESEARCH DESIGN
The symbol used to depict the designs are ;
R –
Random assignment of subjects to groups
X – Experimental treatment or intervention
O – Observation or measurement of dependent variables.
RO1 – Number of treatments

15. EXPERIMENTAL DESIGNS There are three broad categories
True experimental design
Quasi –experimental design
Pre-experiment design

16. TRUE EXPERIMENTAL DESIGN
There are two randomized groups, one receiving the experimental treatment and one receiving no treatment, a placebo treatment, or the usual treatment.
Comparison of pre-test scores allows evaluation of the effectiveness of randomization in providing equivalent groups.
The treatment is under the control of the researcher.
The dependent variable is measured twice, before and after the manipulation of the independent variable

17. ESSENTIAL ELEMENTS OF EXPERIMENTAL DESIGN
Randomization
Controlled manipulation
Control or comparison group

18. TYPES OF TRUE EXPERIMENTAL DESIGNS
PRE-TEST POST- TEST ONLY DESIGN
POST TEST ONLY DESIGN
SOLOMON FOUR GROUP DESIGN
FACTORIAL DESIGN
RANDOM BLOCK DESIGN
CROSS OVER DESIGN

19. 1. Pretest-posttest control group design
Most frequently used experimental design, In this
design,
the subjects are randomly assigned to groups,
a pre-test is given to both groups,
the experimental group receives the experimental treatment and the comparison group receives the routine treatment or no treatment, and
a post-test is given to both groups.

20. Example
Random assignment
Experimental group
Pre test
Treatment
Post test
Control group
Pretest
No treatment
An experimental study to assess the effectiveness of dry ginger powder on management of nausea and vomiting among antenatal mothers residing in a selected area Bangalore

21. Post-test only control group design:
In some studies, the dependent variable cannot be measured before the treatment.
Is composed of two randomly assigned group- experimental and control group
Both the groups are not tested previous to introduction of an intervention .
Treatment is implemented on the experimental group only,
post test observation are made on both the groups .

22. Example
Random assignment
Experimental group
Treatment
Post test
Control group
No treatment
A study to assess the effectiveness of smoking cessation promotion on control of smoking among smokers

23. Randomized block design
Randomized block design is used when the researcher desires to bring homogeneity among selected groups.
The randomized block design uses the two-group pre-test post-test pattern or the two group post test pattern with one addition, a blocking variables
Contd ….

24. The blocking variable, if uncontrolled, is expected to confound the findings of the study.
To prevent confounding of the findings, the subjects are rank ordered in relation to the blocking variable.

25. Example
To ensure homogeneity among subjects under treatment, researcher randomly places the subjects in homogenous groups (blocks).
Patients with hypertension, patients with hypertension and diabetes, patients with hypertension and heart diseases.
The design looks similar to that of factorial design in structure, but out of two factors one factor is not experimentally manipulated.

26. Study to test the efficacy of three different medications in reducing hypertension
Random assignment
Patients with hyper tension
Medication
Post test
Patients with hypertension and diabetes
Patients with hypertension and cardio vascular diseases -

27. Factorial designs:
Here the researcher manipulates two or more independent variables simultaneously to observe their effects on the dependent variable.
This design is particularly useful when there are more than two independent variables to be tested
This is referred to as a 2 x 2 factorial design.

28. Example
A study to assess the effectiveness of different strategic plan in reduction of blood glucose among diabetic client
Random assignment
RO1
Diet
RO2
RO3
Diet and exercise
RO4
RO5
Control
RO6

29. Solomon Four – Group Design
In the Solomon four –group design,
Subjects are randomly assigned to one of the four groups;
Two of the group, experimental group 1 and comparison group 1, are pretested;  
Contd ….

30. Two of the groups, experimental group 1 and experimental group 2, receive the experimental treatment, whereas two of the groups, comparison group 1 and comparison group 2, receive the routine treatment or no treatment; and
A post-test is given to all four groups

31. Example
Effectiveness of fenugreek verses bitter guard juice in reduction of blood glucose among diabetic client
Random assignment
RO1
Fenugreek
R02
Routine treatment
RO2
Bitter guard juice
RO3
No treatment

32. CROSS OVER DESIGN Contd ….
In cross over design the study subjects are exposed to more than one treatment. It is also known as “repeat measure design”.
This design is more efficient in establishing the highest possible similarity among subjects exposed to different conditions where groups compared obviously have equal distribution of characteristics.
Contd ….

33. Some times this design is not effective because, when subjects are exposed to two different conditions, their responses of the second condition may be influenced by their experience in the first condition.

34. Example
Effectiveness of fenugreek verses bitter guard juice in reduction of blood glucose among diabetic client
Random assignment
RO1
Fenugreek
Bitter guard juice
R02
RO2
RO3

35. ADVANTAGES OF TRUE EXPERIMENTAL DESIGN
Most powerful design to establish the causal relationship between independent and dependent variable.
Since the study is conducted under controlled environment, it can yield a greater degree of purity in observation.
Contd ….

36. Conditions that are not found in natural setting can be created in experimental setting in a short period of time that may take years to naturally occur (therefore very useful in genetic studies).
Because the experiment is carried out in experimental setting the problems of real life situations and the personal problems of the researcher is eliminated.

37. DISADVANTAGES OF TRUE EXPERIMENTAL DESIGN
Most often the results of experimental designs cannot be replicated in studies conducted on humans due to ethical problems.
Many of the human variables neither have valid measurable criteria nor instruments to measure them.

38. Quasi-experimental designs
INTRODUCTION
Quasi experimental research design involves the manipulation of independent variable to observe the effect on dependent variable.
The study unlike true experimental study lacks at least one of the three cardinal characteristic (Randomization, Control)
Contd ….

39. Quasi experimental designs have an element of manipulation.
Quasi experimental designs are generally used to establish the causality (effect of independent variable on dependent variable) in situations where researchers are not able to randomly assign the subjects to groups for various reasons.

40. CHARACTERISTICS
Manipulation of the independent variable to observe the effects of the dependent variables.
It lacks at least one of the two other essential characteristics of the true experiment
Quasi independent variables are used instead of true independent variables and independent variable is not manipulated in complete controlled situations.
Contd ….

41. TYPES The two important type of quasi experimental design are
INTERRUPTED TIME SERIES DESIGN
NON EQUIVALENT CONTROL GROUP DESIGN

42. 1. Non Randomized control group designs:
It is also known as “ non-equivalent control group design” in this study the control group is not selected by random means. Some groups are more non-equivalent than others, and some quasi-experimental designs involve using groups (control and treatment) that have evolved naturally rather than being developed randomly.
Contd ….

43. These groups cannot be considered equivalent because the individuals in the control group may be different from individuals in the treatment group.
Individuals have selected the group in which they are included rather than being selected by the researcher.  

44. Post operative patients
Example
Post operative patients
Experimental
group
Pretest
Music
therapy
Post test
Control
------
Effectiveness of music therapy in reduction of pain among Post operative patients admitted in medical surgical

45. 2.Interrupted Time-Series Designs:
The interrupted time-series design is similar to descriptive time designs except that a treatment is applied at some point in the observations. Time-series analyses have some advantages over other quasi-experimental designs.
Contd ….

46. repeated pre-test observations can assess trends in maturation before the treatment.
the repeated pre-test observations allow measures of trends in scores before the treatment, decreasing the risk of statistical regression, which would lead to misinterpretation of findings.

47. Example
To assess the Infection rates among surgery patient data is collected for 3 months and then a new clean procedure is introduced
Infection rates are collected for 3 months thereafter to see if there are any differences over time.
Effectiveness of new cleaning procedure used in ward in presenting of infection.

48. O O O3 X O O O6
The time series design with its numerous observations or measurements of the dependent variables helps to strengthen the validity of the design

49. ADVANTAGE
Quasi experimental designs are more frequently used because they are more practical and feasible to conduct research.
Where the sample size is small, and where randomization and availability of control group is not possible, this design is preferred.
Contd ….

50. Quasi experimental design is more suitable for real natural world setting than true experimental designs.
This design allows the researchers to evaluate the impact of quasi independent variables under naturally occurring conditions.
In some cases hypotheses are practically answered through this design.

51. DISADVANTAGE
In this design there is no control over extraneous variables influencing the dependent variable.
The absence of a control group and absence of control over the research setting makes the result of this design less reliable and weak for the establishment of causal relationship between independent and dependent variable.

52. PRE EXPERIMENTAL DESIGN
This design is considered very weak design .
The researcher has little control over the research

53. Types There are two types of pre-experimental One shot case design
One group pre test post test design .

54. 1.The One-Group post test only Design
One short case study
a single group is exposed to an experimental treatment and observed after the treatment
there is no random assignment of the subjects to the experimental group
There is no control group .

55. Example
Effectiveness of meditation in reduction of anger among adults attending meditation class.
X O

56. The one-group pre-test post-test design
Is the simplest type of pre experimental design, where only the experimental group is selected as the study subject .
A pre test observation of the dependent variable is made prior to the implementation of the treatment to the selected group.
Contd ….

57. afterwards the treatment is administered, and finally a post test observation of dependent variable is carried out to assess the effect or treatment on the group.
It provides a comparison between a group of subjects before and after the treatment.
There is no control group in this design

58. Example
A study to assess the effectiveness of planned teaching programme on knowledge regarding selected oncologic emergencies among nurses .
O1 X O2

59. ADVANTAGES
 Is a very simple and convenient design that helps the researcher to conduct studies in natural settings.
It is most suitable for beginners

60. DISADVANTAGE
Is considered very weak experimental design to establish causal relationship between independent and dependent variables because it controls no threat to internal validity.
It has a higher threat to internal validity of research.
May have selection bias, which is a very serious threat.

61. Non experimental design
All experimental design can not be conducted with human beings because of ethical reasons.
At this time non experimental design can be used.

62. Types Category Research design Non experimental research design
Descriptive design
Correlational design / Ex post facto design
Developmental research design
Epidemiological design
Survey research design

63. Descriptive design 
Feature
Univarient descriptive design
Studies under taken to describe the frequency of occurrence of a phenomenon rather than to study relationship
Exploratory descriptive design 
Investigating the phenomenon and its related factors about which very little is known
 Comparative descriptive design 
comparing occurrences of a phenomenon in two or more groups

64. Correlational design Correlational design Feature Prospective design
Retrospective design
Examining the relationship between two or more variables in a natural setting with out manipulation or control (cause and effect relationship)

65. Developmental Research Design
 Feature
CROSS SECTIONAL DESIGN
LONGITUDINAL DESIGN
Examining the phenomenon only at one point in time.
Examining the phenomenon at more than one point in time

66. Epidemiological Designs Epidemiological
Feature
1.Case control
2.Cohort studies
The studies investigation of distribution
Causes of diseases in a population

67. SURVEY RESEARCH DESIGN
Features
Survey studies are investigation in which self reported data are collected from sample with the purpose of describing population on some variables of interest

68. Example
A study to assess the knowledge , attitude and acceptance of infertile couple regarding recent advancements in infertility management .

69. Conclusion
Exploratory ,descriptive and explanatory studies are classified according to the amount of knowledge about the variables of interest .
Experimental research is concerned with cause and effect relationship taking care of the extraneous variables, internal validity, and external validity with random assignment.
Contd ….

70. Quasi experimental designs are those in which there is either no comparison group or no random assignment of subjects to groups.
Pre-experimental designs are those in which the researcher has little control .