Measurement

While people measure things casually in daily life, research measurement is more precise and controlled. Variables being studied in research may be classified as objects or as properties. –Objects include tangible items such as furniture, laundry detergent, people or automobiles. –Properties are the characteristics of the object. A person's physical properties include weight, height etc., and his psychological properties are attitudes and intelligence. An event is measured in terms of its duration; For duration, one measures the number of hours and minutes recorded.

Measurement For what happened, one uses some system to classify types of activities that occurred. Measurement typically uses some sort of scales to classify or quantify the data collected. There are four scale types. In increasing order of power, they are nominal, ordinal, interval, and ratio

Measurement Four scales are:  Nominal; ordinal, interval, and ratio.  Nominal scales classify without indicating order, distance, or unique origin;  Ordinal data show magnitude relationships of more than and less than but have no distance or unique origin;  Interval scale have both order and distance but no unique origin;  Ratio scales possess all of these feature.

Measurement contd. A.Store Customers: Nominal – Group them by race, ethnic background, married or single status, etc. Ordinal – Rank them as very frequent buyers, frequent buyers, infrequent buyers.

Measurement contd. Interval – Some scale of attractiveness in which the scale is presumed to be interval. Ratio – Average size of monthly purchases

Measurement contd. B.Voter Attitudes Nominal – grouped as Republican, Democrat, Independent, and other; Ordinal – Rank of candidates in order of preference; Interval – Likert – type scale; Ratio – Count of votes for various candidates in each district.

Measurement contd. C.Common Stock Preference Nominal – Industry classification of preferred stocks; Ordinal – Rank order of preference stocks as your preference for them;

Measurement contd. Interval – Rating of preference for the stock by converting the results of a paired comparison rating into presumed interval scale; Ratio – Six-month changes in price of various preferred stocks.

Measurement contd. D.Division Profitability Nominal – Classification of sources of Division profits, e.g. manufacturing, assembly, trading, price changes, etc. Ordinal – Ranking of divisions by the size of their dollar profit 2020; Interval – Use of Semantic Differential scale in evaluating the profit performance image of various divisions; Ratio – Dollar profits for each division in 2020.

Characteristics of Good Measurement Three major criteria for evaluating a measurement tool are: validity, reliability, and practicality. –Validity is the extent to which a test measures what we actually wish to measure. –Reliability has to do with the accuracy and precision of a measurement procedure. –Practicality is concerned with a wide range of factors of economy, convenience, and interpretability

Characteristics of Good Measurement Two major forms of validity are: External and Internal. –The external validity of research findings is the data ability to be generalized across persons, settings, and times; –The internal validity is the ability of a research instrument to measure what it is purported to measure. Does the instrument really measure what its designer claims it does?