King Fahd University of Petroleum & Minerals Department of Management and Marketing MKT 345 Marketing Research Dr. Alhassan G. Abdul-Muhmin Measuring Attitudes and Other Psychological Constructs Reference: Zikmund, Chapter 14 Learning Objectives • At the end of the discussion you should be able to: 1. Identify and describe the basic approaches to measuring attitudes and other psychological constructs 2. Identify and describe the characteristics of different types of ratings scales used in measuring attitudes and other constructs 3. Discuss the major issues to be addressed in choice of rating scales Some Approaches to Measuring Hypothetical Constructs (e.g. Attitudes) Following are approaches that have been used to measure psychological constructs: Physiological Measures, e.g.: 1. – – – – Galvanic skin response (Galvanometer). Pupil dilations (Pupilometer). Eye Movement (Eye-tracking equipment). Voice-pitch levels. 2. Observation of overt behavior. 3. 4. Indirect (Projective) techniques. Subjects’ self-reports a) Choice b) Ranking c) Sorting d) Rating • • Attitude rating scales Selecting a measurement scale Rating Scales Measurement scales that allow a respondent to register the degree (or amount) of a characteristic or attribute possessed by an object directly on the scale. Six main types of rating scales: 1. 2. 3. 4. 5. 6. Category scale Semantic differential scale Stapel scale Likert scale (Summated ratings scale) Constant sum scale Graphic scale Category Scale • A rating scale which the response options provided for a closed-ended question are labeled with specific verbal descriptions. Example: Please rate car model A on each of the following dimensions: a)Durability b)Fuel consumption Poor [ ] [ ] Fair [ ] [ ] Good [ ] [ ] V.good [ ] [ ] Excellent [ ] [ ] Characteristics: • Response options are still verbal descriptions. • Response categories are usually ordered according to a particular descriptive or evaluative dimension. • Therefore scale has ordinal properties. • However, researchers often assume that it possesses interval properties => but this is only an assumption. ** One special version is the Simple category scale. Simple Category Scale • A category scale with only two response categories (or scale points) both of which are labeled. Example: Please rate brand A on each of the following dimensions: poor excellent a) Durability [ ] [ ] b) Fuel consumption [ ] [ ] Semantic Differential Scale • A rating scale in which bipolar adjectives are placed at both ends (or poles) of the scale, and response options are expressed as “semantic” space. Example: Please rate car model A on each of the following dimensions: Durable Low fuel consumption ---:-X-:---:---:---:---:--- Not durable ---:---:---:---:---:-X-:--- High fuel consumption Characteristics 1. The scale has properties of an interval scale. 2. Sometimes descriptive phrases are used instead of bipolar adjectives, especially when it is difficult to get adjectives that are exact opposites 3. It is often used to construct an image profile. Stapel Scale • A simplified version of the semantic differential scale in which a single adjective or descriptive phrase is used instead of bipolar adjectives. Characteristics 1. The scale measures both the direction and intensity of the attribute simultaneously. 2. It has properties similar to the semantic differential. Example: Model A -3 -2 -1 Durable Car 1 2 3 -3 -2 -1 Good Fuel Conaumption 1 2 3 Constant-Sum Scale • • A rating scale in which respondents divide a constant sum among different attributes of an object (usually to indicate the relative importance of each attribute). Assumed to have ratio level properties. Example: Divide 100 points among the following dimensions to indicate their level of importance to you when you purchase a car: Durability Fuel Consumption Total 100 Numerical Scale • Any rating scale in which numbers rather than semantic space or verbal descriptions are used as response options. Examples: Poor Durability 1 2 Durable 1 2 3 3 4 4 5 5 6 Excellent 6 7 7 Not durable Graphic Ratings Scales • • Rating scales in which respondents rate an object on a graphic continuum, usually a straight line. Modified versions are the ladder scale and happy face scale. Characteristics 1. The straight line scale has ratio level properties. 2. The ladder and happy face scales have properties depending on the labeling option chosen – whether all response categories are labeled (ordinal properties) or only the scale end-points are labeled (interval properties). The Likert Scale (Summated Ratings Scale) • A multiple item rating scale in which the degree of an attribute possessed by an object is determined by asking respondents to agree or disagree with a series of positive and/or negative statements describing the object. • Example: Attitude toward buying from the Internet Totally disagree Disagree Neutral a) Shopping takes much longer on the Internet [ ] [ ] [ ] b) It is a good thing that Saudi consumers have the opportunity to buy products through the [ ] [ ] [ ] c) Buying products over the Internet is not a sensible thing to do [ ] [ ] [ ] Agree [ ] Totally agree [ ] [ ] [ ] [ ] [ ] Characteristics of the Likert Scale • 1. 2. 3. 4. • The following procedure is used to analyze data from Likert scales: First, weights are assigned to the responses options, e.g. Totally agree=1, Agree=2, etc Then negatively-worded statements are reverse-coded (or reverse scored). E.g. a score of 2 for a negatively-worded statement with a 5-point response options is equivalent to a score of 4 on an equivalent positive statement. Next, scores are summed across statements to arrive at a total (or summated) score. Each respondent’s score can then be compared with the mean score or the scores of other respondents to determine his level of attitude, loyalty, or other construct that is being measured Note that the response for each individual statement is expressed on a category scale. Characteristics Different Types of Rating Scales Subject must: Advantages Disadvantages 2.Category scale Indicate a response category Flexible, easy to respond Ambiguous items, few categories, only gross distinction. 3. Likert scale Evaluate statements on a 5-point scale Easiest scale to construct Hard to judge what a single score means 4. Semantic differential and numerical scales Choose points between bipolar adjectives on relative dimensions Easy to construct, norms exist for comparison, e.g. profile analysis Bipolar adjectives must be found, data may be ordinal, not interval 5. Constant sum scale Divide a construct sum among response alternatives Scale approximates an interval measure Difficult for respondents with low education levels 6. Stapel scale Choose point on scale with 1 center adjective Easier to construct than semantic differential Endpoints are numerical, not verbal. 7. Graphic scale Choose a point on a continuum Visual impact, unlimited scale points No standard answers 8. Graphic scale-picture response Choose a visual picture Visual impact, easy for poor readers Hard to attach a verbal explanation to response Rating Scale 1. Simple attitude scaling Issues In Selecting A Measurement Scale 1. 2. 3. Whether to use single or index measure. Whether to use a ranking, sorting, choice, or rating scale. Whether to use monadic or comparative scale. • • • 4. 5. Monadic rating scale is one in which respondents evaluate an object in isolation Comparative scale s one in which the object is evaluated in relation to other objects Construction and labeling is different for monadic and comparative scales Whether to use category labels or not. If the decision is to use category labels, what labels to use. Issues In Selecting A Measurement Scale 6. Number of response options (scale categories) to use, i.e whether to use 2, 3, 4, 5, etc response categories • 7. In general, the larger the number of categories the more sensitive the scale is; but also the more difficult it is for respondents to answer Whether to use balanced or unbalanced scale. • A balanced scale has an equal number of points to the left and right of a mid-point. An unbalanced scale has more response options on one side than the other 8. Whether the scale should force choice among the response categories, i.e should the scale contain a “neutral” or “don’t know” category.