fresearch design

8/6/2019 Fresearch Design

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MEMBERS

SHARMISTHA DAS

KOUSTAV CHATTERJEE

MOUMITA DAS ARPAN PAUL

ARGHYA PRATEEM GHOSH


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TYPES OF DESIGN

After-Only Design.

Before and After Design.

Control Group Design. Comparative Study Design.

Matched Control Design.

Placebo Design.

Blind Studies

Double blind studies.


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AFTER-ONLYDESIGN

Here the researcher knows that a population is being or has

been exposed to an treatment.

Hence he wishes to study the impact of the same on the

population.

Study PopulationStudy Population

Treatment

TIME

Beforeobservation

Postobservation


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LIMITATIONS & USEFULNESS

Limitations

The two sets of data are not comparable.

There is no control group available.

Hence no way to find out the impact of extraneous variables.

Usefulness

1. Widely used in impact assessment studies.


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EXAMPLES

Impact of random breath testing on road accidents.

The impact of health program on the mortality of a population. Launching new products.


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BEFOREAND AFTER DESIGN

Here we construct the before observation by establishing it

before the introduction of treatments.

Introducing the treatment.

Carefully observe the post study population to determineeffect of the treatment.

Study Population Study Population

Treatment

TIME

Beforeobservation

PostObservation


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LIMITATION & USEFULNESS

Limitations:

No control group is introduced.

Hence we can not determine the effect of extraneous variables

in possible changes of the data.

Usefulness:

1. The main advantage of this design is we can compare

before and post observations.


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EXAMPLE

First measure the height, weight and stamina of a group of

students.

Then provide them a particular product (Treatment)which

supposed to increase the said attributes. After the specified period again measure the same attribute and

determine whether the treatment changed the dependent

variable or not.


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CONTROL-GROUP DESIGN

Researchers select two population groups

instead of one.

Experimental Group

Control Group


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CONTROL GROUP DESIGN CONTD.



Treatment

Control Group

Experimental

Group

P1 P1

P2 P2


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P1-P1=A=The effect of treatment.

P2-P2=B=The effect of Extraneous variable.

A-B=Actual effect of treatment.


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Groups are comparable to almost every aspect except the

introduction of treatment.

Before observation are made on both the groups at the same

time. Experimental group is exposed to the treatment.

Control group is not.

Though researchers evaluate post observation of both the

group.


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LIMITATION AND USEFULNESS

Limitation:

It can not compare the effectiveness of multiple treatment.

Usefulness:

1. Comparability.

2. Evaluation of effect of extraneous variable.


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COMPARATIVE STUDYDESIGN

It is useful when researchers want to compare

the effects of multiple treatments.

This study can be carried out either as an experiment or as an

non-experiment method.


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EXPERIMENTMETHOD

The study population is divided into the same number of

groups as the number of treatments to be tested.

For each group the before study population is established.

Different treatment models are introduced to different groups. After observation is carried out to determine the change in

the dependent variable.

The degree of change in outcome helps researchers to

determine the effectiveness of each treatment model.


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EXPERIMENTMETHOD CONTD.




Treatment P1

Treatment P2

Treatment P3

P1

P1

P2

P2

P3 P3


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P1-p1=The effect of treatment P1.

P2-P2=The effect of treatment P2.

P3-P3=The effect of treatment P3.


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NON-EXPERIMENT

Here groups that already receiving different treatments are

indentified.

Hence only the post observations are evaluated to specify

the changes in dependent variables, if any..


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MATCHED CONTROL DESIGN

Here the comparability is determined on an individual-by-

individual basis.

Two almost identical individual(sample) are selected from a

population. Each is allocated to different group.

Then one group is identified as experimental group and other

one is control group.

The identification is done through randomization.


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EXAMPLE

Most commonly used in the testing of new drugs.


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PLACEBO DESIGN

Placebo design attempts to determine the

extent of psychological effect.

It involves two or three groups.

First group can recive the treatment.

The second group is exposed to the placebo effect.

The third group receives nothing.


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Treatment

Control

Placebo

Experimental Group

P1

Placebo Group P2

Control Group

P3

P1

P2

P3


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P1-P1=A=Effect of treatment.

P2-P2=B=Effect of Placebo effect.

P3-P3=C=Effect of extraneous variable.

A-B=The actual effect of treatment.

B-C=The actual effect of placebo.


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BLIND STUDIES

Here the study population doesnt know that a

research is being done on them.

Objective:

To isolate the placebo effect/psychology effect.


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EXAMPLE

Like in the earlier case if researchers dont let patients know

about their treatments, the placebo effect of that patient will

be isolated.


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DOUBLE-BLIND STUDIES

Very similar to blind studies.

But here the researchers dont know the identity of

experimental group.

Used to eliminate researchers biasness.


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EXAMPLE

Neither the researcher nor the patient know who is getting real

and who is getting fake treatment.

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