Measurement scaling reliability and validity
- 2. TOPIC TO DISCUSSED The four types of scales –Nominal –Ordinal –Interval –Ratio
- 3. SCALE A scale is a tool or mechanism by which individuals are distinguished as to how they differ from one another on the variables of interest to out study. The scale or tool may be a gross one in the sense that it only broadly categorizes individuals on the on certain variables, or it may be a fine-tuned tool that differentiates individuals on the variables with varying degrees of sophistication.
- 4. NOMINAL SCALE Observation can be named without particular order or ranking imposed on the data.Words, letters, and even numbers are user to classify the data. EXAMPLE: Gender M – Male F – Female
- 5. ORDINAL SCALE Describes rankings or orders.The difference or ratio between two rankings may not always be the same. EXAMPLE: Competition Placement 1- Champion 2- 1st Runner up 3- 2nd Runner up 4- 3rd Runner up
- 6. INTERVAL LEVEL Indicates an actual amount (Numerical).They order and the difference between the variables can be known. Its limitation is it has no “true zero”. EXAMPLE: Temperature 60 °C 20 °C 10 °C -15 °C
- 7. RATIO LEVEL It has the same properties as the interval level.The order and difference can be described. Additionally, it has a true zero and the ratio between two points has a meaning. EXAMPLE: Mass 80 kg 40 kg 10 kg 0 kg
- 9. RATING SCALES The following rating scales are often used in organizational research. Dichotomous scale Category scale Semantic differential scale Numerical scale Itemized rating scale Likert scale Fixed or constant sum rating scale Staple scale Graphic rating scale Consensus scale Other scales, such as the Thurstone Equal Appearing Interval Scale, and the multi-dimensional scale,are less frequently used.We will briefly describe each of the above attitudinal scales.
- 10. DICHOTOMOUS SCALE The dichotomous scale is used to elicit a Yes or No answer, as in the example below. Note that a nominal scale is used to elicit the response. Do you own a car? Yes No
- 11. CATEGORY SCALE The category scale uses multiple items to elicit a single response as per the following example.This also uses nominal scale is used to elicit the response. Where in London do you reside? —East London —South London —West London —North London —Outskirt
- 12. SEMANTIC DIFFERENTIAL SCALE Semantic Differential Scale is a rating scale used to measure the attitudes and opinions of respondents toward an object, person, event, or idea. It uses a set of bipolar adjectives, such as “good-bad,”“happy- sad,”“strong-weak,” etc., placed at opposite ends of a continuum. Responsive ------------------ Unresponsive Beautiful ------------------ Ugly Courageous ------------------- Timid
- 13. NUMERICAL SCALE The numerical scale is similar to the semantic differential scale, with the difference that numbers on a five point or seven –point scale are provided, with bipolar adjectives at both ends, as illustrated below. This is also an interval scale. EXAMPLE How pleased are you with your new estate agent? Extremely pleased 7654321 Extremely displeased
- 14. ITEMIZED RATING SCALE Itemized rating scales are used to help the researcher obtain a measure of attitudes . The researcher first develops a number of dimensions –attitude statements ,product or service attributes ,image dimensions ,etc. Respondents are then asked to position how they feel each one using a defined rating scale.
- 15. LIKERT SCALE