Research Methodology and StatisticChapter 4: Conceptual research 

design Dr. Supakit Nootyaskool

IT‐KMITLsupakitnootyaskool@gmail.com

Objective

• To give idea planning research design.• To explain kinds of selecting a study design.

Topics

4.1 Research design4.2 Selecting a study design

4.1 Research designMeaning

Kerlinger, 1986: 276

“Research design is a plan structure andstrategy of investigations enable one toobtain answers to research questions”

Selltiz, 1962 “Research design is the arrangement ofconditions for collection and analysis ofdata in the manner that aims tocombine relevance of research purposewith economy in process”

4.1 Research designMeaning

Cooper and Schindler, 2003

“Summarizes the essential of researchdesign as an activity and time basedplan; always based on the researchquestion; guide the selection of sourcesand types of information; a frameworkfor specifying the relationship amongthe study variables and outlines theprocedures for every research activity. ”

4.1 Research designMeaning

Thyer, 1993: 94

“A traditional research design is ablueprint or detailed plan for how aresearch study is to be completed—operationalizing variables so they canbe measured selecting a sample ofinterest to study, collecting data to beused as a basis for testing hypothesis,and analyzing the results ”

4.2 Selecting a study designType of  study 

design

Number of contacts

one

cross‐sectional study

two

before and after study

three

longitudinal study

Reference period

Retrospective

Prospective

Retrospective‐prospective

Nature of the investigation

experimental

non‐experimental

semi‐experimental

4.2.1 Cross‐sectional study

Babbie 1989:89 “Designed to study some phenomenon by taking a cross section of it on time” The study from a cross section is easily design by doing:

1. Define study population, after that sample population in a group to study.

2. Collect with questionnaire and check studying result3. One contact collecting data

Cross section (n) กลุ่มตวัอย่าง, การตดัขวาง On time (idm) ทนักําหนด

4.2.1 Cross‐sectional study: questionnaire

4.2.1 Cross‐sectional study: result

4.2.2 Before and after design study

The study does two period of times. 

Difference  = AfterResult – BeforeResult

A situation

BeforeStudy Before After

Study After

4.2.2 Before and after design study: Example1

T25 after 8weeks

4.2.2 Before and after design study: Example2

4.2.2 Before and after design study: regression effect (ผลกระทบการถดถอย)

A situation

BeforeStudy Before After

Study After

4.2.3 Longitudinal study

4.2.3 Longitudinal study

• Longitudinal study– More than one time collecting data

• Regression effect

4.2.3 Longitudinal study: regression effect (ผลกระทบการถดถอย)

A situation

Study1 Study2 Study3

4.2.4 Retrospective study

Retrospective is analysis on the past of the situation from having information.  Dividing into three groups:

1. retrospective study (past)2. Prospective study (future)3. Retrospective‐prospective study (past<‐>future)

Retrospective (adj) ระลึกถึงความหลงั มองยอ้นอดีต Prospective (adj) ทีค่าดหวงัไว้

Prospective S.Retrospective S.At present

4.2.4.1 Retrospective study

2011 Thailand flood 1979 Energy Crisis

4.2.4.2 Prospective study

4.2.4.2 Retrospective ‐ Prospectivestudy

• Joking

4.2.5 Nature of Investigation in research study

• The research that find out the truth has three kinds.– Experimental study– Non‐experimental study– Semi‐experimental study

4.2.5 Nature of Investigation in research study

• The research that find out the truth has three kinds.– Experimental study– Non‐experimental study– Semi‐experimental study

Consist of:• The after‐only design

The before‐and‐after designThe double‐control designThe comparative designThe placebo designBlind studyDouble‐blind study

4.2.5.1 Experimental study: After‐only design

4.2.5.2 Experimental study: Before and after design

ChangeVar = AfterVar – BeforeVar

NN

H = N = 20H = 10N = 20

DataSize 100

Recog

90%

Recog.

90%

Before—Normalize data setTraining time = 1.5sec% Recognition  = 90%

After—Normalize data setTraining time = 1.5sec% Recognition  = 95.5%

4.2.5.3 Experimental study: Double control design

Control1

AfterBefore

Control1

Control2 Control2

4.2.5.4 Experimental study: Placebo design

ยา/แป้ง

แป้ง

ยา

Placebo (n) ยาทีไ่ม่มีฤทธิ์

4.2.5.5 Experimental study: single‐blind study

an experiment in which the person collecting data knows whether the subject is in the control group or the experimental group, but subjects do not known.

4.2.5.1 Experimental study: Double‐blind study

double‐blind study ‐ an experimental procedure in which neither the subjects of the experiment nor the persons administering the experiment know the critical aspects of the experiment; "a double‐blind procedure is used to guard against both experimenter bias and placebo effects"

Reference

• http://www.youtube.com/watch?v=HYuxE3YetQo