156927727 Week 5 Unit 1 Experimental Research

7/23/2019 156927727 Week 5 Unit 1 Experimental Research

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Experimental Research

Chapter 8


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Introduction

Explanatory research

Research that seeks to explain the cause of a

phenomenon, and typically asks what causes

what? or why is it this way?


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Introduction

Causal hypothesis

A testable expectation about an independent

ariable!s affect on a dependent ariable


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Introduction

Causal hypotheses and experimental desi"ns#$ Empirical association

%$ &emporal precedence or time order

'$ (on)causal relationship


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Introduction

Causal hypotheses and experimental

desi"ns Experimental desi"ns

A study desi"n in which the independent ariable

is controlled, manipulated, or introduced in some

way by the researcher


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Introduction

&he classic experiment* +ata collectiontechniue or study desi"n? -n experimental desi"n the independent

ariable is introduced, manipulated, orcontrolled .hat does this mean?

&he independent ariable does not occur naturally,but it is the result of an action taken by the researcher

/niue feature of the classic experimental desi"n &he researcher controls the placement of sample

members into two or more cate"ories of theindependent ariable


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Introduction

&he classic experiment* +ata collectiontechniue or study desi"n? -fpractical and ethical, a study can be

desi"ned so that the dependent ariable ismeasured first and then,the independentariable is introduced or manipulated and,finally, the dependent ariable is measureda"ain$ Can see whether the introduction of the

independent ariable comes before chan"einthe dependent ariable$


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Experimental Designs

Control "roup

Exposed to allthe influences that the

experimental "roup is exposed to exceptfor

thestimulus


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Stimulus

&he experimental condition of the independent ariable

that is controlled or introduced by the researcher in

an experiment

&he researcher tries to treat the two "roups exactly

alike, except instead of the stimulus, the control

"roup receies no treatments, an alternatie

treatment, or a placebo


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Placebo

A simulated treatment of the control "roup that

is desi"ned to appear authentic


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Internal validity

A"reement between a study!s conclusions

about causal connections and what is actually

true


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Experimental desi"n

pretest)posttest control "roup experiment

Classic controlled experiment

An experimental desi"n with two or morerandomly selected "roups 0an experimental and

control "roup1 in which the researcher controls or

introduces the independent ariable and

measures the dependent ariable at least two

times 0pretest and posttest measurement1


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Experimental desi"n


2retest

&he measurement of the dependent ariable thatoccurs before the introduction of the stimulus of

independent ariable


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Experimental desi"n


2osttest

&he measurement of the dependent ariable thatoccurs after the introduction of the stimulus or the

independent ariable


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Experimental desi"n


2robability samplin"

A sample that "ies eery member of thepopulation a known 0non3ero1 chance of inclusion


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4 Experimental desi"n


4 Random Assi"nment A techniue for assi"nin" members of the sample to

experimental and control "roups by chance to maximi3e thelikelihood that the "roups are similar at the be"innin" of the

experiment

&his can be done by flippin" a coin to determine which sub5ect

is assi"ned to which "roup

Assi"n each sub5ect a number and usin" either a randomnumber table or electronic random number "enerator to select

members of each "roup


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4 Experimental desi"n


4 6atchin"

Assi"nin" members of the sample to "roups bymatchin" members of the sample on one or

more characteristics and separatin" the pairs

into two "roups with one "roup randomly

selected to become the experimental "roup


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Experimental desi"n


#$ &he study uses at least one experimental and one

control "roup, selected usin" a strate"y to make the"roups as similar as possible

%$ &he dependent ariable is measured at least two time

for the experimental and control "roups$ &he first

measurement is before and the second is after the

independent ariable is introduced


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Experimental desi"npretest)posttest control "roup experiment

'$ &he independent ariable is introduced, manipulated, orcontrolled by the researcher between the two measurements ofthe dependent ariable$7$ &he differences in the dependent ariable between thepretest and posttest are calculated for the experimental "roup0s1and for the control "roup$ &he differences in the dependentariable for the experimental and control "roups are compared$


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-nternal alidity and experiments

6aturation &he biolo"ical and psycholo"ical processes

that cause people to chan"e oer time


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&estin" effect &he sensiti3in" effect on sub5ects of the

pretest


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istory&he effects of "eneral historical eents

on study participants


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9election biasA bias in the way the experimental and

control or comparison "roups areselected that is responsible for

preexistin" differences between the

"roups$


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2osttest)only control "roup experiment

An experimental desi"n with no pretest Either because it is not possible to do a pretest or

because of a concern that usin" a pretest wouldsensiti3e the experimental "roup to the stimulus

9ame desi"n elements as other experiments*

control of manipulation of the stimulus and two or

more "roups usin" random selection or

assi"nment


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Extended experimental desi"n

9olomon four)"roup desi"n A controlled experiment with an additional

experimental and control "roup with eachreceiin" a posttest only


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:uasi)experimental desi"n

An experimental desi"n that is missin" one or

more aspects of a true experiment

6ost freuently random assi"nment intoexperimental and control "roups

/sed when it is not ethical or practical to do a

controlled experiment


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Experiments in the field

;ield experiment An experiment done in the real world of

classrooms, offices, factories, homes,play"rounds, and the like


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Experiments in the field


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Focal Research

A ;ield Experiment in the Classroom by Chris

Caldeira

ypothesi3ed that usin" film clips to teach

sociolo"ical concepts in con5unction with thetextbook and lecture is more effectie in

helpin" students learn core concepts than the

lecture and textbook without the clips$


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Experiments in the laboratory

Laboratory research Research done in settin"s that allows the

researcher control oer the conditions, such as ina uniersity or medical settin"

Research examples

ob3a and Aaron Rochlen 0%==>1

ushman and Anderson 0%==>1


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Experiments in the laboratory

-mportant to ealuate a study!s external

validity@ or the ability to "enerali3e the

results from the laboratory to the real world


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Experiments in the laboratory External alidity @ -ssues to Consider

#$ .as the situation ery artificial, or did it approximate reallife?

%$ ow different were study participants from otherpopulations?

'$ &o what extent did the participants beliee that they wereup for inspection, serin" as "uinea pi"s or play actin", orhae other feelin"s that would affect responses to the

stimulus?

7$ &o what extent did the researcher communicate his or herexpectations for results to the sub5ects with erbal ornonerbal cues?


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Experiments in the laboratory Experimenter expectations

.hen expected behaiors or outcomes are

communicated to sub5ects by the researcher Bne way to handle the issue of experimenter

expectationsis to use a double-blind

experiment.


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Experiments in the laboratory Double-blind experiment

An experiment in which neither the sub5ects nor

research staff who interact with them knows thememberships of the experimental or control

"roups$


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(atural experiments

A study usin" a real)work phenomena that

approximates an experimental desi"n een

thou"h the independent ariable is notcontrolled, manipulated, or introduced by the

researcher


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(atural experiments

.ars, hurricanes, political eents mi"ht

effect some "roups and not others$

Example 9tudyin" the of deployment on military families

&he researcher cannot control deployment, but two

"roups could be created by those families who were

deployed and those families who were not deployed


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Comparing Experiments to Other

Designs

6any research uestions cannot be studied

usin" experimental desi"n

Dar"e samples are reuired

(ot practical, ethical, and possible tomanipulate the independent ariable

-n these scenarios researchers may consider

panel, trend, cross)sectional, or case study

desi"ns


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Summary

9tudy desi"n options

Refer to &able 8$% ) 9ummary of +esi"n

9tudies

-ssues to consider in desi"nin" a study Ethical considerations

2racticality &ime

Cost

;easibility of controllin" the independent ariable


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Quiz Question 1

An experimental desi"n has the adanta"e oer

non)experimental approaches of determinin"

the order in which eents occur and

a$ controllin" the effects of other ariables$b$ minimi3in" the costs of the research$

c$ accommodatin" ethical concerns$

d$ proin" conclusiely that a relationship is

causal$


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Quiz Question

-n a classic experimental desi"n, it is important

to take measures of control and experimental

"roups

a$ before and after treatment$b$ at least once durin" the research$

c$ after the treatment$

d$ before the treatment$

e$ it is not important to take measures$


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Quiz Question !

-n experimental desi"ns, it is important that the

control "roup and the experimental "roup

a$ are as similar as possible$

b$ represent ery different "roups so that theresearch is "enerali3able$

c$ do not come from the same back"round$

d$ receie the same treatment$

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156927727 Week 5 Unit 1 Experimental Research