Research Design New

RESEARCH DESIGN Research design is the arrangement of conditions for collection and analysis of data in a manner that aims to combine relevance to the research purpose with economy in procedure. (OR) Research design constitutes the blue print for the collection, measurement and analysis of data. It aids the scientist in the allocation of his limited resources by posing crucial choices.

RESEARCH DESIGN • NEED FOR A RESEARCH DESIGN – It facilitates the smooth sailing of the various research operations – It yields maximum information with minimum expenditure of effort, time and money – To organize ideas and how to overcome the flaws and inadequacies in the process.

The Nature of Good Design • Theory-Grounded. Good research strategies reflect the theories which are being investigated. Where specific theoretical expectations can be hypothesized these are incorporated into the design.

The Nature of Good Design • Situational. Good research designs reflect the settings of the investigation. For example, when a particular need of teachers and administrators was explicitly addressed in the design strategy. Similarly, intergroup rivalry, demoralization, and competition might be assessed through the use of additional comparison groups who are not in direct contact with the original group.

RESEARCH DESIGN Important Concepts Relating to Research Design • The group in an experiment which receives the specified treatment is called the Treatment Group or the experimental group. However, the term Control Group refers to another group assigned to the experiment, but not for the purpose of being exposed to the treatment. Thus, the performance of the control group usually serves as a baseline against which to measure the effect of the full treatment on the treatment group.

Important Concepts Relating to Research Design • Variance refers to the variability of any event. If one uses a fine enough measuring device, one can find differences between any two objects or events. • Blocks usually refers to categories of subjects with a treatment group. For example, we might divide the group into older, middle aged, and younger patients and further divide the groups into a group treated with Drug A and another treated with Drug B. The advantage is to enable us to discover how the treatment affects each of the age groups. For example, we might find that overall, Drug B out performs Drug A, except for older patients, where Drug A out performs Drug B. This phenomenon is known as an interaction between treatment (the Drug) and subject characteristics (age).

Important Concepts Relating to Research Design • Dependent and Independent Variable : – If one variable depends upon or is a consequence of the other variable is termed as an dependent variable. – The variable that is antecedent to the dependent variable is termed as an independent variable. – Extraneous Variable : Independent variables that are not related to the purpose of the study, but may affect the dependent variable are termed as extraneous variables.

Important Concepts Relating to Research Design • Confounded relationship: When the dependent variable is not free from the influence of extraneous variable(s), the relationship between the dependent variable and independent variables is said to be confounded by an extraneous variable(s).

Important Concepts Relating to Research Design • Research Hypothesis: When a prediction or a hypothesized relationship is to be tested by scientific methods • Experimental hypothesis-testing research: When the purpose of research is to test a research hypothesis is termed as experimental hypothesis-testing research. • Non-Experimental hypothesis-testing research: A research in which an independent variables are not manipulated.

Important Concepts Relating to Research Design • Experimental and Control Group: In an experimental hypothesis-testing research when a group is exposed to usual conditions, it is termed a ‘control group’, but when the group is exposed to some novel or special treatment, it is termed as ‘experimental group’.

Important Concepts Relating to Research Design • Treatments: The different conditions under which experimental and control groups are put are usually referred to as “ treatments”. • Experiment: The process of examining the truth of a statistical hypothesis, relating to some research problem, is known as an experiment. • Experimental Units: The pre-determined plots or the blocks, where different treatments are used, are known as experimental units.

Types of Research Design Research Design

Exploratory/ Formulative

Descriptive/ Diagnostic

Overall Design Flexible Rigid Design Design( design ( Design must must provide make enough an opportunity provision for for considering protection different against bias aspects of the and maximum problem reliability)

Types of Research Design Sampling Design

Non-probability Probability sampling sampling design design ( purposive or ( random judgment sampling) sampling

Statistical Design

No pre-plannedPre-planned design for design for analysis analysis

Types of Research Design Observational Unstructural Structured or Design instruments for well thoughtcollection of out data instruments for collection of data Operational Design

No fixed decisions about operational procedures

Advance decisions about operational procedures

CHAPTER-4

EXPERIMENTAL RESEARCH DESIGNS

EXPERIMENTAL RESEARCH DESIGNS

Experimental Designs refers to the framework or structure of an experiment.

Experimental Design An experimental design is a set of procedures specifying – the test units and how these units are to be divided into homogeneous subsamples, – what independent variables or treatments are to be manipulated, – what dependent variables are to be measured, and – how the extraneous variables are to be controlled.

Basic Principles of Experimental Designs • The Principle of Replication : The experiment should be repeated more than once. • The Principle of Randomization: Provides protection, when we conduct an experiment, against the effect of extraneous factors by randomization • The Principle of Local Control: Blocking

Controlling Extraneous Variables • Randomization refers to the random assignment of test units to experimental groups by using random numbers. Treatment conditions are also randomly assigned to experimental groups. • Matching involves comparing test units on a set of key background variables before assigning them to the treatment conditions. • Statistical control involves measuring the extraneous variables and adjusting for their effects through statistical analysis. • Design control involves the use of experiments designed to control specific extraneous variables.

Experimental Design Experimental Design refers to the framework or structure of an experiment Informal Formal Experimental Experimental Design Design Before & After without control design

Complete Randomized Design

After-only with control design

Randomized Block Design

Before & After with control design

Latin Square Design

Informal Experimental Design

• Before and After without control Design:

In such a design a single test group or area is selected and the dependent variable is measured before the introduction of the treatment. The treatment is then introduced & the D.V is measured again after the treatment has been introduced.

Test area: Level of phenomenon Phenomenon Before treatment( X ) treatment( Y)

Treatment introduced

Treatment Effect = (Y)-(X)

Level of after

Before-and-after without control design • Main difficulty-passage of time considerable extraneous variations may be there in treatment effect

•

Informal Experimental Design After only with control Design :

In this design two groups or areas are selected and the treatment is introduced into the test area only. The D.V. Is then measured in both the areas at the same time

Test area: Treatment introduced Phenomenon

Level of after

treatment( Y) Control Area Level of phenomenon

After only with control design • Assumption-two areas are identical with respect to their behaviour

Informal Experimental Design • Before and After with Control Design: In this design two areas are selected and the D.V. is measured in both the areas for an identical time-period before the treatment. The treatment is then introduced into the test area only, and the D.V. is measured in both for an identical time period after the introduction of the treatment.

Before and After with Control Design: Time Period I Time Period II Test Area: Level of Phenomenon Level of phenomenon before treatment ( X) after treatment( Y) Treatment introduced Control Area: Level of Phenomenon without treatment( A)

Level of phenomenon without treatment ( Z)

Treatment Effect = ( Y-X) - (Z-A)

BEFORE AND AFTER WITH CONTROL DESIGN • Superior-it avoids extraneous variation • Non comparibility of test and control areas • At times due to lack of historical data,time and comparable control area

Formal Experimental Design Complete Randomized Design ( C.R.Design) Involves only two principle – The principle of replication – The principle of Randomization – Subjects are randomly assigned to experimental treatments – When all the variations are due to uncontrolled extraneous factors are included under the heading of chance variation, we refer to the design of experiment as C.R.Design.

Complete Randomized Design ( C.R.Design) • Two Group Simple randomized design: population

Randomly selected sample

experimental

T;A

Randomly assigned

I.V control

T:B

Complete Randomized Design ( C.R.Design) • Random Replication Design: It serves two purposes • It provides controls for the differential effects of extraneous independent variables • It randomizes any individual differences among those conducting the treatments

Formal Experimental Design • Randomized Block Design ( R.B.Design) – All the three principles are taken care off – In this the subjects are divided into groups, known as blocks, such that within each group the subjects are relatively homogenous in respect to some selected variable. – Each treatment appears the same number of times in each block – R.B.Designs are analyzed by the two way analysis of variance ( two way ANOVA) technique.

Randomized Block Design ( R.B.Design) V.Low I.Q

Low I.Q

Average I.Q

Student Student Student Form1

Form4

Student Student

82

67

57

71

73

90

68

54

70

81

Form2 Form3

High I.Q V.High I.Q

69 86

73

51

93

77

60

65

84 71

Randomized Block Design • Is useful when there is only one major external variable, such as store size, that might influence the dependent variable. • The test units are blocked, or grouped, on the basis of the external variable. • By blocking, the researcher ensures that the various experimental and control groups are matched closely on the external variable.

Table 7.4

Block Store Number Patronage 1 2 3 4

Heavy Medium Low None

Randomized Block Design Treatment Groups Commercial Commercial Commercial A B C A A A A

B B B B

C C C C

Formal Experimental Design • Latin Square Design ( L.S.Design) – Very frequently used in agricultural research. – Used when there are two major extraneous factors – The treatment in L.S. are so allocated among the plots that no treatment occurs more than once in any row or column – Five types of fertilizer ABCDE $Two blocking factors(varying soil fertility$varying seeds) may be represented through rows and columns. – Two way ANOVA technique is used. – 5x5 to 9x9

Latin Square Design • Allows the researcher to statistically control two noninteracting external variables as well as to manipulate the independent variable. • Each external or blocking variable is divided into an equal number of blocks, or levels. • The independent variable is also divided into the same number of levels. • A Latin square is conceptualized as a table (see Table 7.5), with the rows and columns representing the blocks in the two external variables. • The levels of the independent variable are assigned to the cells in the table. • The assignment rule is that each level of the independent variable should appear only once in each row and each column, as shown in Table 7.5.

Table 7.5

Latin Square Design Interest in the Store

Store Patronage

High

Heavy Medium Low and none

B C A

Medium A B C

Low C A B

Latin Square Design ( L.S.Design) I

II

III

IV

V

X1

A

B

C

D

E

X2

B

C

D

E

A

X3

C

D

E

A

B

X4

D

E

A

B

C

X5

E

A

B

C

D

Factors affecting Research Designs • • • • • •

Non availability of the sufficient data Availability of Time Availability of resources Ability of the Researcher External Factors Result Desired

VALIDITY • By validity, we mean simply that the researcher’s conclusion is true or correctthat it corresponds to the actual state in the world. Validity is an indicator of accuracy in terms of the extent to which a research conclusion corresponds to reality.