Measurement in communication research การวัดในงานวิจัยด้านการสื่อสาร

Research Questions Does internet usage decrease family interaction? Are fear appeal messages more likely to affect teenage sexual practices than one that do not? What do customers think about sale representatives performance?

Why measures? Reality check Reality = X X = facts + error

Questionnaire (Consumer satisfaction) (a) And, on these issues relating to customer service, how important on a scale from 1 to 5 is "sales reps know the products and their applications"? RATE ALL ISSUES FOR IMPORTANCE. (b) And how satisfied are you with your main supplier on each of these issues (a) (b) CUSTOMER SERVICE Importance Satisfaction Sales reps know the products and their applications 4 3 Sales reps are prompt in returning calls/follow ups 5 2 Company reps solve problems fast 2 1 Complete and accurate invoicing 4 1 Internet/electronic ordering 1 1 Good relationships with reps 4 1 Regular contact from the rep 2 1

Where do questions come from? Conceptual definitions and search scholarly discussions Decide on format Feedback from a small sample Examine reliability and validity

Who are you? Tell me about yourself.

Testing a gun!

Testing a gun!

Testing a gun!

Reliability (ความน่าเชื่อถือ - ความคงเส้นคงวา) Definition: internal consistency of a measure (same situation) A part of the facts collected The gun keeps shooting at the same area most of the time. The gun is reliable!!!

Validity (ความถูกต้อง - ความแม่นยำ) Definition: consistency of a measure with a criterion (Across situations) You get the answers to questions being asked. You aim the gun at the bullseyes but it keeps shooting at the same area most of the time. The gun is reliable, but not valid!

Methods for measurement (p.214-215) Likert scale Semantic differential Guttman Thurstone Multidimensional scaling

Likert scale Statements that yield responses that range from favorable to unfavorable toward an object. (measuring attitudes) Agree - Disagree

Semantic differential - Measure the meanings that an object has for an individual Beautiful - Ugly Good - Bad Large - Small

Guttman -

Thurstone Predefined values associated with each statement

Multidimensional scaling (MDS) how similar or how different certain objects are perceived to be. Places the objects in a spatial relationship to one another A list of objects asked to make judgments about how similar the items are.

Processing the data Describing - Information Explaining - Rationales

Can u calculate…? ID Number Gender Ranking Average scores Percentage

Level of Measurement Nominal data (นามบัญญัติ) Ordinal data (เรียงลำดับ) Interval data (อันตรภาค) Ratio data (อัตราส่วน)

Types of reliability Test-retest reliability (ก่อน-หลัง) Alternate forms reliability (ต่างคำถาม) Split-half reliability (แบ่งครึ่ง-แบ่งคำถามทั้งหมดเป็น 2 ส่วน) Item to total reliability (แต่ละข้อ) Intercoder reliability (ระหว่างคนโค้ดข้อมูล) Statistical shortcuts Cronbach coefficient alpha

Test-retest reliability (ก่อน-หลัง) Before - after the test

Alternate forms reliability (ต่างคำถาม) Same concepts different questions How old are you? What year did you finish high school?

Split-half reliability แบ่งครึ่ง-แบ่งคำถามทั้งหมดเป็น 2 ส่วน Odd-even numbered Odd-even reliability

Intercoder reliability (ระหว่างคนโค้ดข้อมูล) Content analysis Different coders

Statistical shortcuts Cronbach coefficient alpha

Question: If you administer a research twice with the same set of questions, what type of reliability will you seek?

Types of validity Face (Content) validity Expert jury validity Criterion validity (เกณฑ์) Concerrent validity Predictive validity (คาดการณ์) Construct validity (โครงสร้าง)

Face (Content) validity

Expert jury validity Developing questionnaires

Criterion validity (เกณฑ์) Ability to predict a score on some other measure or to predict a particular behavior of interest. The measure predict arelevant behaviors and responses on a second measure SAT, GRE test predicting college performance

Criterion validity (เกณฑ์) Concerrent validity new measures with previously measure of the same thing Updated measures Predictive validity (คาดการณ์) a measure predicts known groups that the construct exists

Construct validity (โครงสร้าง) Concerning with what is being measured Theoretical based - Relationship that are predicted according to the theory found Trust of another person leads to increased levels of negative self-disclosure (bad things stated about oneself)

Questions: If you develop a questionnaire, what kind of validity that you would seek to validate the questionnaire?