Research Methods in MIS Dr. Deepak Khazanchi

Variables: Operational Definitions A statement which defines a variable by specifying the operations used to measure and manipulate it. Vs. Conceptual definitions (more dictionary like) Variable in research Problem: Computer usage by end users Labeling the variable: Attitudes towards computer usage Operational Definition: An individual’s score on the attitudes towards computer usage instrument

Measurement of Variables Measurement: Assigning numbers to objects or events according to rules Measurement is used in every research project Determine the level of measurement for each variable Decide if the level of measurement could be changed to a higher level, and if this would improve the research Review validity and reliability in order to critique the literature and for later use at the instrumentation stage

Measurement By definition, measurement implies a three-part process: Selecting observable empirical events Developing a mapping rule: a scheme for assigning numbers or symbols to represent aspects of the events being measured Applying the mapping rule(s) to connect the observation to the symbol

One Example Assume you are studying people who attend a computer show where all of the year’s new products are on display. You are interested in learning the male-to-female ratio among attendees. You observe those who enter the show area. If a person is female, you record an F; if male, an M. Any other symbols such as 0 and 1 or % and # also may be used if you know what group the symbol identifies.

What is Measured? Variables being studied may be classified as objects or properties. Objects include: Things of ordinary experience (e.g., people, tables, books, computer systems, etc.) Some things not concrete (e.g., attitudes, genes, neutrons, etc.) Properties are: Characteristics of objects Physical properties (e.g., weight, height, etc.) Psychological properties (e.g., attitudes, perceptions, etc.) Social properties (e.g., leadership ability, status, etc.)

Characteristics of Data Mapping rules for data have four characteristics: Classification Numbers are used to group or sort responses. No order exists. Order Numbers are ordered. One number is greater than, less than, or equal to another number. Distance (interval between numbers) Differences between numbers are ordered. The difference between any pair of numbers is greater than, less than, or equal to any other pair of numbers. Origin of number series The number series has a unique origin indicated by the number zero.

Levels of Measurement Order Interval Origin Nominal none none none Ordinal yes unequal none (e.g., Doneness of meat: well, medium well, medium rare, rare) Interval yes equal or none unequal (e.g., Temperature in degrees) Ratio yes equal zero (e.g., Age in years) NOTE: Nominal is the lowest and Ratio is the highest level of measurement.With higher levels of measurement, more precise statistical tests can be used.

THE FOUR LEVELS OF MEASUREMENT: NOMINAL Nominal Level of Measurement Lowest level of measurement because numbers are assigned to variables only to classify or categorize them. Categories are mutually exclusive Typical statistics used: chi-square or other nonparametric statistics Example: Nature of investment (Stocks = 1 or Bonds = 2)

THE FOUR LEVELS OF MEASUREMENT: ORDINAL Ordinal Level of Measurement Numbers are used to: Classify or Rank Example of assigning numbers: Rank of TV Stations: ABC=1, CBS=2, Fox=3) Numbers Indicate: Difference Greater than or less than The number assigned must maintain order in the numbering system Typical statistics used: Mean, sign test or other nonparametric statistics

THE FOUR LEVELS OF MEASUREMENT: INTERVAL Interval Level of Measurement Numbers are used to classify, rank, indicate equal units, indicate an arbitrary zero point. Numbers Indicate: Difference, Greater than or less than, equal distance between numbers, zero does not indicate absence of variable. Permissible arithmetic operations: Counting, ranking, addition, subtraction Typical statistics used: Mean, t-test or other parametric test

Interval Level of Measurement In social science research, researchers assume interval level of measurement for variables which are probably more accurately measured at on ordinal level. Scales that use responses with labels such as “very important” (coded as 3), “somewhat important” (coded as 2), and “not very important” (coded as 1) are used in social science research so that statistical calculations and tests appropriate for interval data can be used The assumption that the distance between the scale numbers such as “very important” and “somewhat important” is equal to that between “somewhat important” and “not very important” is questionable and should be analyzed as ordinal data.

THE FOUR LEVELS OF MEASUREMENT: RATIO Nominal Level of Measurement Numbers are used to classify, rank, indicate equal units, indicate absolute zero. Example of assigning numbers: Income or Age. Numbers Indicate: Difference, Greater than or less than, Equal distance between numbers, Zero indicates absence of the variable. Permissible arithmetic operations: Counting, Ranking, Addition, Subtraction, Multiplication, Division. Typical statistics used: Geometric mean, t-tests or other parametric statistics

RATIO AND ORDINAL LEVELS Example of Ratio level questions NOTE: This is the only measure that can be used to make proportional statements like something is twice something else. What was your income last year? Example pf changing ratio level to ordinal level In which category was your income last year? 1. Above $50,000 2. $30,000 to $50,000 3. Below $30,000

Summated Rating Scales (Likert-Type ) In MIS and other social science research, Likert-type interval scales (ratings) are used to assess subjects attitudes, opinions, etc. toward an object by summing, and sometimes averaging, over all items. This assumes that each item in a measurement is of “equal value” to each respondent The response categories, usually degrees of disagreement and agreement, must be the same for all items The measurement for the construct “PERCEIVED USEFULNESS OF MIS” utilizes 12 items that respondents rate on a Likert-type interval scale ranging from “Not at all” to “Very much.” E.g., To what extent do you actually use this system compared to your original expectations?

Semantic-Differential Scales Measure the meaning of concepts by selecting a concept and then choosing a series of bipolar adjectives to which subjects respond on a 7 point rating scale. E.g., user information satisfaction construct uses a 39 item semantic differential scale. Analyses can take many forms: comparing concepts, groups of Ss or even factors. Sometimes scores are summed for adjectives measuring the same factor. Graphical analysis is a common tool used for this type of scale.

Where you are now Determined the level of measurement of each variable Decided if the level of measurement could and should be changed to a higher level, and recognized that The level of measurement determines the statistical techniques