Evaluating Research_Blok1_2014.ppt

8/9/2019 Evaluating Research_Blok1_2014.ppt

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EVALUATING YOUR RESEARCH

DESIGNZen Hafy


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Variables

The research variables, of any scienticexperiment or research process, are factors thatcan be manipulated and measured.

The key to designing any experiment is to lookat what research variables could aect theoutcome.

There are many types of variable but the mostimportant, for the vast majority of researchmethods, are the independent and dependent variables.

https://explorable.com/design-of-experimenthttps://explorable.com/independent-variablehttps://explorable.com/independent-variablehttps://explorable.com/design-of-experiment


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Variables

The independent variable is the core of theexperiment and is isolated and manipulatedby the researcher.

The dependent variable is the measurableoutcome of this manipulation, the results ofthe experimental design.


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ependent!ariable" #eight

$oss

%ndependentvariable" food intake

%ndependentvariable" exercise

regimen

Variables


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&ause and eect relationships are establishedby manipulating the INDEPENDENT variable's( and observing the eect on theDEPENDENT variable.

)esearch design must control for the possible

eects of extraneous variables thatcould mask, enhance, or in some way alter

the eect of the independent variable on thedependent variable.

Variables


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Internal Validity" determined by the degree towhich the observed eects of the independentvariable '%!( are )*+$ and not caused byextraneous factors

Alternative explanationsAlternative explanations for the eect of theindependent variable '%!( on the dependentvariable '!( threaten internal validity

*-" adequate controlling for the possibleeects of extraneous variables

Internal & External Validity


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%nternal !alidity the /soundness/ or 01uality2of the research design

0did manipulation of the independent variable

truly cause the changes seen in thedependent variable or were confoundingin3uences present to such a degree as toundermine study results 42

The better the research design, the higher theinternal validity.


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Confounding

onfounding variables 'or third variables(are variables that the researcher failed tocontrol, or eliminate, damaging the internalvalidity of an experiment.

%t can adversely aect the relation betweenthe independent variable anddependent

variable.


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Confounding


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Components of Internal Validity

%nitial *1uivalence 5rior to manipulation of the causal variable,

participants in the dierent conditions are the same

'on the average( on all measured6subject variables

7ngoing *1uivalence during manipulation of the causal variable, completion

of the task, and measurement of the eect variable,participants in the dierent conditions are the same'on the average( on all manipulated6proceduralvariables except the causal variable.


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Relationships cause & effect

&orrelation of ice cream sales and death bydrowning 'r 8 9.:;(

%n the months when ice cream sales go up, so

do deaths by drowning and likewise when icecream sales go down, so do deaths by drowning

+.( oes ice cream consumption cause

drowning deaths to increase4 or


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External Validity" determined by the ability togenerali=e the study results beyond the study sample

>uestion addressed here is"

0are the results of the study applicable to a population42

0To what groups, settings, experimental variables, andmeasurement variables can these ndings begenerali=ed2

*-" adequate sa!pling !ethod" a study cannot have external validity#ithout internal validity

Internal & External Validity


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A Hierarchy of Population


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A Hierarchy of Population

5opulasi *ksternal

5opulasi Target

5opulasi +ktual6?umber

5opulasi studi 'sampel(

Validitas Eksternal

Validitas Internal

Inferensi Statistik


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Types of External Validity

@. 5opulation external validity" identifying thepopulation to which results may begenerali=able.

A. *cological external validity" concerned withgenerali=ing experimental eects to otherenvironmental conditions 'i.e., settings(.


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Bias

$esearch bias, also called experimenterbias, is a process where the scientistsperforming the research in3uence the results,in order to portray a certain outcome.


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a. Design Bias

esign bias is introduced when the researcher fails to take

into account the inherent biases liable in most typesof experiment.

b. Selection Bias (omission and inclusive bias)

7ccurs when the process of sampling actually introducesan inherent bias into the study

c. Procedural Bias

5rocedural bias is where an unfair amount of pressureis applied to the subjects, forcing them to completetheir responses 1uickly.


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d. Measurement BiasBeasurement bias arises from an error in thedata collection and the process of measuring.

e. Interviewer Bias#ith interviewer bias, the interviewer maysubconsciously give subtle clues in with bodylanguage, or tone of voice, that subtly in3uence

the subject into giving answers skewed towardsthe interviewerCs own opinions, prejudices andvalues.


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f. Response Bias)esponse bias is a type of bias where thesubject consciously, or subconsciously, givesresponse that they think that the interviewer

wants to hear.

g. Reporting Bias

)eporting


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TD+E -7F

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Evaluating Research_Blok1_2014.ppt