Measurement in Survey Research MKTG 3342 Fall 2008 Professor Edward Fox

Measurement in Survey Research numbers labels rules Measurement is the process of assigning numbers or labels to the attributes of objects, persons, states, or events in accordance with specific rules

Identify the concept of interest Identify the concept of interest Develop a construct Develop a construct A constitutive definition A constitutive definition An operational definition An operational definition A measurement scale A measurement scale Evaluate the reliability and validity of the scale Evaluate the reliability and validity of the scale Utilize the scale Utilize the scale Research findings Research findings The Measurement Process …which is used to create… …which enables a researcher to develop … …which enables a researcher to create… …that requires the researcher to… If the evaluation is satisfactory, the researcher… …which leads to… …which is used to…

Steps 1&2: Identify Concept / Develop Construct Identify the concept of interest Identify the concept of interest Develop a construct Develop a construct A constitutive definition A constitutive definition An operational definition An operational definition A measurement scale A measurement scale Evaluate the reliability and validity of the scale Evaluate the reliability and validity of the scale Utilize the scale Utilize the scale Research findings Research findings

Steps 1&2: Identify Concept / Develop Construct Measurement begins by identifying a concept of interest and the construct to be studied. Both are abstractions of reality. A concept is expressed in every-day terminology. This requires the researcher to generalize/categorize. A construct is a theoretical abstraction that can’t really be observed (e.g., love, trust, social class, personality, power).

Steps 1&2: Identify Concept / Develop Construct – Example Question – Why do some customers buy Air Jordan athletic shoes over and over again? Concept – Repeat purchase Construct – Brand loyalty

Steps 3&4: Define the Concept Conceptually and Operationally Identify the concept of interest Identify the concept of interest Develop a construct Develop a construct A constitutive definition A constitutive definition An operational definition An operational definition A measurement scale A measurement scale Evaluate the reliability and validity of the scale Evaluate the reliability and validity of the scale Utilize the scale Utilize the scale Research findings Research findings

Steps 3&4: Define the Concept Conceptually and Operationally Constitutive Definition A theoretical or conceptual definition that defines the concept in terms of other concepts and constructs; like a dictionary definition Operational Definition Defines which observable characteristics will be measured and the process for assigning a value to the concept

Steps 3&4: Define the Concept Conceptually and Operationally – Example Constitutive Definition – Increased propensity to purchase a brand due to previous experience with that brand Operational Definition – Rating of purchase probability, depending upon prior purchase

Step 5: Develop a Measurement Scale Identify the concept of interest Identify the concept of interest Develop a construct Develop a construct A constitutive definition A constitutive definition An operational definition An operational definition A measurement Scale A measurement Scale Evaluate the reliability and validity of the scale Evaluate the reliability and validity of the scale Utilize the scale Utilize the scale Research findings Research findings

Step 5: Develop a Measurement Scale SCALE A scale is a set of symbols or numbers so constructed that the symbols or numbers can be assigned by a rule for the individuals (or their behaviors or attitudes) to whom the scale is applied

Types of Scales   Nominal Description Uses numerals to identify objects, individuals, events, or groups. Used for Classification (male/female; buyer/nonbuyer) Typical Descriptive Statistics Frequency counts, percentages/modes Examples of Nominal Scales Gender(1) Male(2) Female Geographic Area (1) Urban (2) Rural (3) Suburban

Types of Scales   Ordinal Scale Description In addition to identification, the numerals provide information about the relative amount of some characteristic; determines greater or less than Typical Descriptive Statistics Median Example of Ordinal Scale: Please rank the following fax machines from 1 to 5 with 1 being the most preferred and 5 the least preferred. _____ Panasonic _____ Toshiba _____ Sharp _____ Savin _____ Ricoh

Types of Scales   Interval Description Has all the properties of nominal and ordinal scales + equal intervals between consecutive points; preferred measure for complex concepts or constructs Typical Descriptive Statistics Mean/variance Example of an Interval Scale Scaled response (on a scale from 1 to 10…)

Types of Scales   Ratio Description Incorporates all the properties of nominal, ordinal, and interval scales plus it includes an absolute zero point Typical Descriptive Statistics Mean/variance + a few higher order statistics Example of a Ratio Scale Age, weight, height, population of the U.S., etc.

Step 5: Develop a Measurement Scale – Example Probability of purchasing the shoe brand again in the next month, next year, or at any point in the future Type of scale?

Step 6: Scale Reliability and Validity Identify the concept of interest Identify the concept of interest Develop a construct Develop a construct A constitutive definition A constitutive definition An operational definition An operational definition A measurement scale A measurement scale Evaluate the reliability and validity of the scale Evaluate the reliability and validity of the scale Utilize the scale Utilize the scale Research findings Research findings

Step 6: Scale Reliability and Validity Step 6: Scale Reliability and Validity Any measurement can be expressed as a function of three components: Any measurement can be expressed as a function of three components: X O = X T + X S + X R Observed Score = True Score + Systematic Error + Random Error Ideally,X O = X T Ideally,X O = X T In Practice,X O  X T … that is, X S + X R  0  Total Error = X S + X R, where  X S = Systematic error (validity)  X R = Random error (reliability)

Step 6: Scale Reliability and Validity – Illustration Not ReliableReliable and ValidNot Valid

Scale Reliability The degree to which measures are free from random “noise” and, therefore, provide consistent data Issues Test-Retest Reliability Internal Reliability (split-half technique)

Scale Validity Addresses the issue of whether what we attempted to measure was actually measured Issues Face Validity Content Validity Predictive Validity Convergent Validity Discriminant Validity

Summary Measurement means using rules to assign numbers to objects in such a way as to represent quantities of attributes The measurement process is as follows: identify the concept of interest, develop a construct, define the concept constitutively and operationally, develop a measurement scale, evaluate the reliability and validity of the scale, and then use the scale There are four basic types of measurement scales: nominal, ordinal, interval, and ratio

Summary (Cont.) Measurement data consists of information (“signal”) and error (“noise”). Validity requires that you actually measure what you intended to measure Reliability is the degree to which measures are free from random error