Introduction to Marketing Research CHAPTERS 9/10: MEASUREMENT AND SCALING Idil Yaveroglu Lecture Notes

Measurement and Scaling Measurement means assigning numbers or other symbols to characteristics of objects according to certain pre-specified rules. One-to-one correspondence between the numbers and the characteristics being measured. The rules for assigning numbers should be standardized and applied uniformly. Rules must not change over objects or time. We assign numbers to the object in such a way as to represent quantities of attributes associated with that object. Height: 1 metre 80 cms, Weight: 85 kg. Number of credit hours earned: 96

General issues in measurement Two essential steps in measurmement process: Construct development Operationalization (The process of assigning descriptors to represent the range of possible responses to a question about a particular object or construct)

General issues in measurement Choosing question-response format: The nature of the property being measured Gender=dichotomous; liking for chocolate=scale Previous research studies Use format in previous study if you’d like to compare The data collection mode Cannot use some scales on the phone The ability of the respondent Kids can’t relate to scaled response The scale level desired for analysis

Scaling: Scale characteristics Scaling involves creating a continuum upon which measured objects are located 1. Description The unique labels or descriptors that are used to designate each value of the scale. All scales possess description. Male/female; yes/no 2. Order The relative sizes or positions of the descriptors are known. Order is denoted by descriptors such as greater than, less than, and equal to.

Scale Characteristics Description By description we mean the unique labels or descriptors that are used to designate each value of the scale. All scales possess description. Male/female; yes/no Order By order we mean the relative sizes or positions of the descriptors. Order is denoted by descriptors such as greater than, less than, and equal to.

Scale Characteristics (Cont.) Distance The characteristic of distance means that absolute differences between the scale descriptors are known and may be expressed in units. 1 YTL difference between 25 YTL and 26 YTL 10 degrees difference between 25 C and 35 C Origin The origin characteristic means that the scale has a unique or fixed beginning or true zero point. Zero market share, zero YTL, zero purchases

An Illustration of Scale Characteristics Age in Years Distance 120 Very Old Description Golden Years 80 Seniors 60 Order Middle Aged 40 Young Adults 20 Youth Origin New Born

Primary Scales of Measurement Lowest level of measurement Primary Scales Nominal Scale Ordinal Scale Interval Scale Ratio Scale Highest level of measurement

Why important? The scale affects what may or may not be said about the property being measured. Examples: If you wish to calculate an average, you must use an interval or ratio scale. If you have a nominal or ordinal scale, you must summarize the results with a percentage or frequency distribution. Nominal scales - Nominal scales are defined as those that use only labels; that is, they possess only the characteristic of description. Ordinal scales - Ordinal scales permit the researcher to rank-order the respondents or their responses. Interval scales - Interval scales are those in which the distance between each descriptor is known. Ratio scales - Ratio scales are ones in which a true zero origin exists—such as an actual number of purchases in a certain time period, dollars spent, miles traveled, number of children, or years of college education. There is a hierarchy of scales; ratio scales are the “highest” and nominal scales are the “lowest.” Nominal scales simply label objects. Ordinal scales indicate only relative size differences between objects. Interval scales use descriptors that are equal distances apart. Ratio scales have a true zero point.

Primary Scales of Measurement: Nominal Scale The numbers serve only as labels or tags for identifying and classifying objects. The numbers do not reflect the amount of the characteristic possessed by the objects. The only permissible operation on the numbers in a nominal scale is counting. Only a limited number of statistics, all of which are based on frequency counts, are permissible, e.g., percentages, and mode. MEAL PREFERENCE: Breakfast, Lunch, Dinner     RELIGIOUS PREFERENCE: 1 = Buddhist, 2 = Muslim, 3 = Christian, 4 = Jewish, 5 = Other     POLITICAL ORIENTATION: Republican, Democratic, Libertarian, Green

Primary Scales of Measurement: Ordinal Scale A ranking scale in which numbers are assigned to objects to indicate the relative extent to which the objects possess some characteristic. An ordinal scale indicates direction, in addition to providing nominal information. Can determine whether an object has more or less of a characteristic than some other object, but not how much more or less. Examples: RANK: 1st place, 2nd place, ... last place   LEVEL OF AGREEMENT: No, Maybe, Yes POLITICAL ORIENTATION: Left, Center, Right In addition to the counting operation allowable for nominal scale data, ordinal scales permit the use of statistics based on centiles, e.g., percentile, quartile, median.

Ordinal Scale

Primary Scales of Measurement: Interval Scale Numerically equal distances on the scale represent equal values in the characteristic being measured. Interval scales provide information about order, and also possess equal intervals. It permits comparison of the differences between objects. Examples: TIME OF DAY on a 12-hour clock   POLITICAL ORIENTATION: Score on standardized scale of political orientation Statistical techniques that may be used include all of those that can be applied to nominal and ordinal data, and the arithmetic mean, standard deviation, and other statistics commonly used in marketing research.

Interval Scale

Primary Scales of Measurement: Ratio Scale Possesses all the properties of the nominal, ordinal, and interval scales. It has an absolute zero point. Using a ratio scale permits comparisons such as being twice as high, or one-half as much. Examples: RULER: inches or centimeters YEARS of work experience   INCOME: money earned last year NUMBER of children   GPA: grade point average All statistical techniques can be applied to ratio data.

Ration Scale

What type of measurement scale? Q1. The following is a question on a survey: Please check the appropriate price range that indicates the amount you spend each week on gasoline for your car: _____ 1. $0.00 - $10.00 _____ 2. $10.01 - $20.00 _____ 3. $20.01 - $30.00 _____ 4. $30.01 - $40.00 Ordinal Scale

What type of measurement scale? (cont’d) Q2. The number of children in a family is an example of what kind of data? Q3. In a survey of luxury car owners, respondents were chosen from 4 states; California, New York, Illinois, and Ohio. What is the level of measurement that is reflected by the states the owners were selected from? RatioScale Nominal Scale

A Classification of Scaling Techniques Comparative Scales Itemized Rating Scales Continuous Noncomparative Paired Comparison Rank Order Constant Sum Stapel Likert Semantic Differential

A Comparison of Scaling Techniques Comparative scales involve the direct comparison of stimulus objects. Comparative scale data must be interpreted in relative terms and have only ordinal or rank order properties.   In noncomparative scales, each object is scaled independently of the others in the stimulus set. The resulting data are generally assumed to be interval or ratio scaled.

Comparative Scaling Techniques: Paired Comparison Scaling A respondent is presented with two objects and asked to select one according to some criterion. The data obtained are ordinal in nature. Paired comparison scaling is the most widely used comparative scaling technique. With n brands, [n(n - 1) /2] paired comparisons are required. Under the assumption of transitivity, it is possible to convert paired comparison data to a rank order.

Paired Comparison Scaling Instructions We are going to present you with ten pairs of shampoo brands. For each pair, please indicate which one of the two brands of shampoo in the pair you would prefer for personal use. Recording Form Jhirmack Finesse Vidal Sassoon Head & Shoulders Pert 1 1A Number of times preferred 3B 2 4 A A 1 in a particular box means that the brand in that column was preferred over the brand in the corresponding row. A 0 means that the row brand was preferred over the column brand. B The number of times a brand was preferred is obtained by summing the 1s in each column.

Comparative Scaling Techniques: Rank Order Scaling Respondents are presented with several objects simultaneously and asked to order or rank them according to some criterion. Possible that the respondent may dislike the brand ranked 1 in an absolute sense. Furthermore, rank order scaling also results in ordinal data. Only (n - 1) scaling decisions need be made in rank order scaling.

Rank Order Scaling Instructions Rank the various brands of toothpaste in order of preference. Begin by picking out the one brand that you like most and assign it a number 1. Then find the second most preferred-brand and assign it a number 2. Continue this procedure until you have ranked all the brands of toothpaste in order of preference. The least preferred brand should be assigned a rank of 10. No two brands should receive the same rank number. The criteria of preference is entirely up to you. There is no right or wrong answer— Just try to be consistent. Brand Rank Order 1. Crest 2. Colgate 3. Aim 4. Mentadent 5. Macleans 6. Ultra Brite 7. Close Up 8. Pepsodent 9. Plus White 10. Stripe

Comparative Scaling Techniques: Constant Sum Scaling Respondents allocate a constant sum of units, such as 100 points, to attributes of a product to reflect their importance. If an attribute is unimportant, the respondent assigns it zero points. If an attribute is twice as important as some other attribute, it receives twice as many points. The sum of all the points is 100. Hence, the name of the scale.

AVERAGE RESPONSE OF 3 SEGMENTS Constant Sum Scaling Instructions Below are eight attributes of bathing soaps. Please allocate 100 points among the attributes so that your allocation reflects the relative importance you attach to each attribute. The more points an attribute receives, the more important the attribute is. If an attribute is not at all important, assign it zero points. If an attribute is twice as important as some other attribute, it should receive twice as many points. Form AVERAGE RESPONSE OF 3 SEGMENTS Attributes Segment I Segment II Segment III 1. Mildness 8 2 4 2. Lather 17 3. Shrinkage 3 9 7 4. Price 53 5. Fragrance 19 6. Packaging 5 7. Moisturising 20 8. Cleaning Power 13 60 15 SUM 100

Relationship of Measurement and Scaling to the Marketing Research Process Step 1 : Marketing Research Problem Definition Step 2 : Approach to the Problem • Specify the information needed Step 3 : Research Design •Use appropriate level of measurement and appropriate scales to measure each item of information •Questionnaire Design: Translate the information needed to appropriate questions using the identified scales Step 4: Fieldwork Administer questions using the identified scales Step 5 : Data Preparation and Analysis: •Use appropriate statistical techniques compatible with the level of measurement of the data Step 6: Report Preparation and Presentation Discuss the statistical results and findings in light of the scales used .

Primary Scales of Measurement Basic Description Scale Characteristics Common Examples Marketing Examples Permissible Statistics Nominal Numbers Identify and classify objects Description Social Security numbers; numbering of football players Brand numbers; store types; sex classification Percentages; mode Ordinal Numbers indicate the relative positions of the objects but not the magnitude of differences between them Order Quality rankings; rankings of teams in a tournament Preference rankings; market position; social class Percentile; median (continued on next slide)

Primary Scales of Measurement (Cont.) Basic Description Scale Characteristics Common Examples Marketing Examples Permissible Statistics Interval Differences between objects can be compared; zero point is arbitrary Description Order Distance Temperature (Fahrenheit, Celsius) Attitudes; opinions; index numbers Range; mean; standard deviation Ratio Zero point is fixed; ratios of scale values can be computed Origin Length; weight Age; income; costs; sales; market shares Geometric mean (All)

Illustration of Primary Scales of Measurement NOMINAL SCALE ORDINAL SCALE INTERVAL SCALE RATIO SCALE No. Jean Brand Preference Ranking Preference Ratings Price ($) 1 - 7 11 - 17 1. Bugle Boy 7 79 5 15 30 2. Calvin Klein 2 25 17 48 3. Diesel 8 82 27 4. Gap 3 6 16 32 5. Guess? 1 10 34 6. Jordache 53 35 Lee 9 95 4 14 8. Levi 61 33 9. Old Navy 45 29 10. Wrangler 115 12 24

Relative Advantages of Comparative Scales Small differences between stimulus objects can be detected. Same known reference points for all respondents. Easily understood and can be applied. Involve fewer theoretical assumptions. Tend to reduce halo or carryover effects from one judgment to another.

Relative Disadvantages of Comparative Scales Ordinal nature of the data. Inability to generalize beyond the stimulus objects scaled.

Noncomparative Scaling Techniques Respondents evaluate only one object at a time Noncomparative techniques consist of continuous and itemized rating scales.

A Classification of Non-comparative Rating Scales Continuous Itemized Semantic Differential Stapel Likert

Continuous Rating Scale Respondents rate the objects by placing a mark at the appropriate position on a line that runs from one extreme of the criterion variable to the other. The form of the continuous scale may vary considerably. Leads to interval scale

Itemized Rating Scales The respondents are provided with a scale that has a number or brief description associated with each category. The categories are ordered in terms of scale position, and the respondents are required to select the specified category that best describes the object being rated. The commonly used itemized rating scales are the Likert, semantic differential, and Stapel scales.

Likert Scale The Likert scale requires the respondents to indicate a degree of agreement or disagreement with each of a series of statements about the stimulus objects.   Strongly Disagree Neither Agree Strongly disagree agree nor agree disagree 1. Sears sells high quality merchandise. 1 2X 3 4 5 2. Sears has poor in-store service. 1 2X 3 4 5 3. I like to shop at Sears. 1 2 3X 4 5 The analysis can be conducted on an item-by-item basis (profile analysis), or a total (summated) score can be calculated. When arriving at a total score, the categories assigned to the negative statements by the respondents should be scored by reversing the scale.

Semantic Differential Scale The semantic differential is a seven-point rating scale with end points associated with bipolar labels that have semantic meaning.   SEARS is: Powerful --:--:--:--:-X-:--:--: Weak Unreliable --:--:--:--:--:-X-:--: Reliable Modern --:--:--:--:--:--:-X-: Old-fashioned The negative adjective or phrase sometimes appears at the left side of the scale and sometimes at the right. This controls the tendency of some respondents, particularly those with very positive or very negative attitudes, to mark the right- or left-hand sides without reading the labels. Individual items on a semantic differential scale may be scored on either a -3 to +3 or a 1 to 7 scale.

Stapel Scale The Stapel scale is a unipolar rating scale with ten categories numbered from -5 to +5, without a neutral point (zero). This scale is usually presented vertically. SEARS +5 +4 +3 +2 +2x +1 High Quality Poor Service -1 -2 -3 -4x -4 -5 The data obtained by using a Stapel scale can be analyzed in the same way as semantic differential data.

Table 10.1 Basic Noncomparative Scales Basic Characteristics Examples Advantages Disadvantages Continuous Rating Scale Place a mark on a continuous line Reaction to TV commercials Easy to construct Scoring can be cumbersome Unless computerized Itemized Rating Scales Likert Scale Degree of agreement on a 1 (strongly disagree) to 5 (strongly agree) scale Measurement of attitudes construct, administer, and understand More time consuming Semantic Differential Seven-point scale with bipolar labels Brand, product, and company images Versatile Difficult to cons-truct bipolar adjectives Stapel Scale Unipolar ten-point scale, -5 to +5, without a neutral point (zero) Measurement of attitudes and construct and administer over telephone Confusing and difficult to apply

Summary of Itemized Rating Scale Decisions 1. Number of categories While there is no single, optimal number, traditional guidelines suggest that there should be between five and nine categories. 2. Balanced vs. unbalanced In general, the scale should be balanced to obtain objective data. 3. Odd or even number of Categories If a neutral or indifferent scale response is possible for at least some of the respondents, an odd number of categories should be used.

Summary of Itemized Rating Scale Decisions (Cont.) 4. Forced versus nonforced In situations where the respondents are expected to have no opinion, the accuracy of data may be improved by a nonforced scale. 5. Verbal description An argument can be made for labeling all or many scale categories. The category descriptions should be located as close to the response categories as possible. 6. Physical form A number of options should be tried and the best one selected.

Balanced and Unbalanced Scales Surfing the Internet is ____ Extremely Good ____ Very Good ____ Good ____ Bad ____ Very Bad ____ Extremely Bad ____ Somewhat Good Balanced Scale Unbalanced Scale

Rating Scale Configurations A variety of scale configurations may be employed to measure the comfort of Nike shoes. Some examples include: Nike shoes are: 1) Place an “X” on one of the blank spaces… Very Very Uncomfortable Comfortable 2) Circle the number… Very 1 2 3 4 5 6 7 Very Uncomfortable Comfortable 3) Place an “X” on one of the blank spaces… Very Uncomfortable Uncomfortable Neither Uncomfortable nor Comfortable Comfortable Very Comfortable

Rating Scale Configurations (Cont.) Very Uncomfortable Somewhat Neither Comfortable nor Uncomfortable Somewhat Comfortable Comfortable Very Comfortable 4) -3 -2 -1 0 1 2 3 Neither Comfortable nor Uncomfortable 5)

Some Unique Rating Scale Configurations Thermometer Scale Instructions: Please indicate how much you like McDonald’s hamburgers by coloring in the thermometer. Start at the bottom and color up to the temperature level that best indicates how strong your preference is. Form: Smiling Face Scale Instructions: Please point to the face that shows how much you like the Barbie Doll. If you do not like the Barbie Doll at all, you would point to Face 1. If you liked it very much, you would point to Face 5. 1 2 3 4 5 100 75 50 25 0 Like very much Dislike very much

Some Commonly Used Scales in Marketing Construct Scale Descriptors Attitude Very Bad, Bad, Neither Bad nor Good, Good, Very Good Importance Not at All Important, Not Important, Neutral, Important, Very Important Satisfaction Very Dissatisfied, Dissatisfied, Neither Dissatisfied nor Satisfied, Satisfied, Very Satisfied Purchase Frequency Never, Rarely, Sometimes, Often, Very Often Copyright © 2012 Pearson Education, Inc. Copyright © 2012 Pearson Education, Inc. Chapter 10 - 49

Developing a Multi-Item Scale Develop the Constraint Develop a Theoretical Definition Develop an Operational Definition Develop a Multi-Item Scale Generate a Pool of Scale Items Reduce the Pool of Items Based on Judgment Collect Data Purify the Scale Based on Statistical Analysis Evaluate Scale Reliability and Validity Apply the Scale and Accumulate Research Findings

Scale Evaluation Scale Evaluation Validity Reliability Content Chapter 10 - 51 Scale Evaluation Reliability Validity Test-Retest Internal Consistency Alternative Forms Construct Criterion Content Convergent Discriminant Nomological

Total Measurement Error Total measurement error is the sum of systematic error and random error. Total measurement error = Systematic error + Random error Systematic error affects the measurement in a constant way, that is, in the same way each time the measurement is made. Random error, in contrast, arises from random changes and has a different effect each time the measurement is made.

Reliability and Validity Recall class on reliability versus validity! Reliability: Test-retest reliability Inter-rater reliability Internal consistency reliability Split-half reliability Cronbach’s alpha Recall: a reliable measure may not be valid! II

Reliability Reliability can be defined as the extent to which measures are free from random error. In test-retest reliability, respondents are administered identical sets of scale items at two different times and the degree of similarity between the two measurements is determined. In alternative-forms reliability, two equivalent forms of the scale are constructed and the same respondents are measured at two different times, with a different form being used each time.

Reliability (Cont.) Internal consistency reliability determines the extent to which different parts of a summated scale are consistent in what they indicate about the characteristic being measured. In split-half reliability, the items on the scale are divided into two halves and the resulting half scores are correlated. The coefficient alpha, or Cronbach's alpha, is the average of all possible split-half coefficients resulting from different ways of splitting the scale items. This coefficient varies from 0 to 1, and a value of 0.6 or less generally indicates unsatisfactory internal consistency reliability.

Validity The validity of a scale may be defined as the extent to which differences in observed scale scores reflect true differences among objects on the characteristic being measured, rather than systematic or random error. Perfect validity requires that there be no measurement error. Content validity is a subjective but systematic evaluation of how well the content of a scale represents the measurement task at hand.

Relationship Between Reliability and Validity If a measure is perfectly valid, it is also perfectly reliable. In this case, there is no random or systematic error. If a measure is unreliable, it cannot be perfectly valid, since at a minimum random error is present. Thus, unreliability implies invalidity. If a measure is perfectly reliable, it may or may not be perfectly valid, because systematic error may still be present. Reliability is a necessary, but not sufficient, condition for validity.