MEASUREMENT, SCALING AND SAMPLING Variables · Nominal variables are variables that have two or...

MEASUREMENT, SCALING AND SAMPLING

Prof. Bijaya G. Shrestha

Variables can be explained in different ways:

Variable simply denotes a characteristic, item, or the dimensions of the concept that increases or decreases

over time, or takes different values in different situations.

For example:

(i) ‘Corporate performance’ can be consider as a concept and NPM,ROA,ROE,EPS, Turnover, Liquidity

are some example of variables. Therefore, concept is a subjective matter that cannot be directly

measured. However, it can be measured through the corresponding variables.

(ii) If we are conducting a research on the problem of social mobility (concept), ethnic group, gender,

age, income level, qualification, location can be considered as variables.

Variable is a symbolic name associated with a value and that may be changed in different circumstances. It

can be any item, factor, condition that can be controlled, changed, or measured in an experiment.

A variable can be measured either using crude or refined method or either using subjective or objective

methods. There are various scales and a variable can be measured on either one of those scales.

Understand the scales of measurement: NOIR

Variables

Independent Variables

[Experimental or Predictor]

Dependent Variable

[Outcome or Criterion]

Training Productivity

Age

Moderating Variables[Conditional or

Interaction]

Mediating Variables[Intervening]

Motivation

Type of Variables

Type of Variables


A variable is called independent if it is not influenced by any other variable under study. An independent variable, sometimes called an experimental or predictor variable, is a variable that is being manipulated in an experiment in order to observe the effect on a dependent variable, sometimes called an outcome variable. A variable is called dependent (criterion) if its values depend upon other variable/s.

Categorical variables are also known as discrete or qualitative variables. Categorical variables can be further categorized as either nominal or ordinal. Nominal variables are variables that have two or more categories, but which do not have an intrinsic order or ranked. Ordinal variables are variables that have two or more categories just like nominal variables but the categories can also be ordered or ranked.

A moderator variable, is a third variable that affects the strength or direction of the relationship between a dependent and independent variable. A moderating variable is a second independent variable that has been selected for study in order to determine if it affects or modifies the basic relationship between the primary independent variable and the dependent variable.

A mediator or intervening variable is that factor which theoretically affects the observed phenomenon but cannot be seen, measured or manipulated because they usually have to do with an individuals feelings e.g. fatigue, boredom, excitement, intention, motivation etc. Intervening variable explains the relationship between the dependent and the independent variables like

Type of Variables


Categorical variables are also known as discrete or qualitative variables. Categorical variables can be further categorized as either nominal or ordinal.

Nominal variables are variables that have two or more categories, but which do not have an intrinsic order or ranked. For example, gender is a categorical variable having two categories (male and female) and we assign the number 1 for male, 2 for female but, there is no intrinsic ordering to the categories. Here, 2 is not higher than 1. The next example, hair color is a nominal variable having a number of categories (blonde, brown, black, red, etc.) and again, we can assign the numbers 1, 2, 3, 4 etc. but, there is no agreed way to order these from highest to lowest. Here, 4 is not higher than 1.

An ordinal variable is similar to a nominal, to some extent. The difference between the two is that there is a clear ordering of the variables in ordinal. For example, suppose you have a variable, economic status, with three categories (low, medium and high). We can order the categories as low, medium and high. Say we assign scores 1, 2, and 3 to these three levels .Even though we can order these from lowest to highest, the spacing between the values may not be the same across the levels of the variables.

If these categories were equally spaced, then the variable would be an interval variable.

Sometimes we have variables that are “in between” ordinal and interval, for example, a five-point likert scale with values “strongly agree”, “agree”, “neutral”, “disagree” and

“strongly disagree”. If we cannot be sure that the intervals between each of these five values are the same, then we would not be able to say that this is an interval variable, but

we would say that it is an ordinal variable.

Type of Variables


A discrete variable is one that can not take value between two numbers. It refers to the one that has a certain number of values. For example: Sibling in a family.

A continuous variable is one that can take any value between two numbers. For example, weight of different individuals: Between 52 and 82 kg, there are a lot of possibilities: One person might be 64.0354 kg weight, and another person might be 72.6709 kg. And, there are literally millions of other possible weights between 62 and 82 kgs. Therefore, a continuous variableimplies the one that can take any value between a given range.

Scales of Measurement

Attitude Measurement and Scale Construction


There are two challenges a researcher faces when measuring an individual's attitude.

First, an individual's attitude toward an object cannot be observed directly but must be inferred from observed behavior, such as responses to a questionnaire.

And second, there is no inherent scale associated with the observed behavior.

Attitude can be defined as a tendency to react favorably, neutrally, or unfavorably toward various aspects of the world. It is a person's inherent qualities of mind and character.

It is a tendency to respond in a certain manner. Attitude is a subjective and personal matter. It is a point of view (a feeling or opinion) about

something or someone that influences an individual's behavior. Therefore, opinion of a person is the verbal expression of attitude.

Attitude can be formed from a person's past and present. The attitude of a person is determined by psychological factors like ideas, values, beliefs, perception, etc.

Measurement is the assignment of numbers to characteristics of something or someone,according to rules. It is oriented to measure something.

The term number given in the definition of measurement are used as symbols/numbers to represent certain characteristics of the object and it does not mean addition, subtraction,

division or multiplication.

Scaling is the way of measurement.

Attitude measurement is the mechanism for measuring the abstract concepts.



Components of Attitude

AffectiveThe feelings or

emotions toward an

object

BehavioralPredisposition or tendency to

action.

CognitiveKnowledge and beliefs about an

object

It represents feelings or emotions that people have toward an object (Joy, happiness, and

satisfaction, anger, frustration etc.). It measures people’s like or dislike for a

particular object. Statements such as "I like this" or "I prefer that" reflect the affective component of an

attitude.

It refers to an intention to act in a certain way toward someone or something.

Affective and Cognitive components are major determinant of the behavioral

component of attitude. An officer gives equal opportunity to

both male and female because he believe that ‘discrimination is wrong.’

It is related to the beliefs, knowledge, and thoughts that people have about the

object.For example: You may have belief in

reincarnation, or rebirth.An officer may have thought that

“Discrimination is wrong"

In an organization,

understanding the attitudes are important for their goal or objective to succeed.

In a typical research of

social science, different

components are measured

by the appropriate

scales.



Attitude measurement relates to the process of measuring an individual's attitude towards an object. When we go for measurement of attitudes or any other parameter, one has to clearly sort out the following :

• "what" has to be measured ?

• "who" is to be measured ?

• the accuracy desired in the measurement

• the costs permissible

• the choices available in the measurement/data collection techniques.

.

In attitude measurement, the researcher is primarily interested in measuring the "state of mind" of

the respondent (s).

It may include factors such as awareness, attitudes and decision processes.

An interesting characteristics of these measures is that their verification is rather difficult.

Ranking, Rating, Sorting and Choice are the techniques (mechanisms) for developing attitude

scales.

Attitude Scales Commonly used in Social Science Research


Likert Scales

Named after its founder, psychologist Rensis Likert, Likert scale is used to understand the level of feeling/agreement/importance etc. that the respondents have on a particular statement.Insightful Likert scale questions plays a greater role in social science research, specially the survey research. Each Likert scale consists of several Likert items. A Likert item is an individual statement or question which asks a person to indicated the extent to which they agree/satisfy/feel the importance/ frequency of using or visiting etc. with several ranked options.Likert items usually offer participants a choice from the several ranked options (e.g.,3; 5;7;9), with the middle option being neutral. The widely used ranked options are 5 and 7. However, there are many evidences of exclusion of the middle point to avoid central tendency error. Therefore, odd and even likert scales are possible

Your level of

satisfaction after using

our products

Highly dissatisfied

Dissatisfied

Neutral

Satisfied

Highly satisfied

The organization is active to

keep the employee updated

with information technology

Strongly disagree

Disagree

Somewhat disagree

Neither agree nor disagree

Somewhat agree

Agree

Strongly agree

A researcher can make

different style of Likert scale

questionnaire.



Semantic Differential Scale

A semantic differential scale is a list of opposite adjectives. The survey answering options are grammatically on opposite adjectives at each end. Sometimes semantic differentials are also known as polarities.The semantic differential scale question asked the respondent to select one (typically from the 7 levels), offering two polarized options.It is the most reliable way to get information on people’s emotional attitude towards a topic of interest. For example, love / hate, simple / complex with intermediate options in between.The respondents’ attitude would be the sum of the numbers corresponding to the positions

checked on the individual subscales (or average).

How do you rate the teen agers of Kathmandu valley on the following dimensions:Gentle ___ : ___ : ___ : ___ : ___ : ___ : ___ ViolentFlexible ___ : ___ : ___ : ___ : ___ : ___ : ___ InflexibleHonest ___ : ___ : ___ : ___ : ___ : ___ : ___ DishonestPessimistic ___ : ___ : ___ : ___ : ___ : ___ : ___ OptimisticEnergetic ___ : ___ : ___ : ___ : ___ : ___ : ___ Unenergetic

Likert and Semantic Differential, both questions serve the same relative purpose. But the way in which the question is asked and the response terms used (as well as how the answer

choices are listed) can make a huge difference.



Stapel ScaleIt is a unipolar (one adjective) rating scale designed to measure the respondent’s attitude towards the object or event.This scale was named after its developer, Jan Stapel. This scale is usually presented vertically. The data obtained by using a staple scale can be analyzed in the same way as a semantic differential data.

There is no neutral point in a staple scale question which means each option can describe the objective.

The semantic differential allows for a neutral point which means that a survey respondent can leave a question unanswered if the thebipolar objectives do not appropriately define the experience.



Rank Order Rating Scales

The rank order rating scale is widely used to measure preference for an object. It focuses on ordinal measurement.

For example:As your feeling, place a ‘1’ next to the brand that is most reliable, a ‘2’ next to the brand that is most reliable, and so on. Remember, no two brands can have the same rating._______ Suzuki_______ Hyundai_______ Mahindra_______ TATA_______ Chevrolet

Numerical ScalesNumerical scales of measuring the attitude uses number options to respondents instead of verbal expressions. It looks similar as Semantic Differential Scales. Because, it also uses bipolar adjectives. But, it provides anumeric symbolization of an attribute and the numbers are provided with interval properties beyond just ordinal properties. It can be 5-point, 7-point and so on. For example, it can be requested to give number to express level of satisfaction in different attributes: Please rate your level of satisfaction with our service: Extremely satisfied 5 4 3 2 1 Extremely dissatisfiedRooms ____Breakfast ____Launch ____Dinner ____Staffs ____

Different types of questions in questionnaire

Demographic questionsMultiple choice questionsSimple category/Dichotomous questionsRanking questionsClose ended questionsOpen-ended questions

Criteria of Good Measurement: Validity and Reliability of Measurement


Types of Validity

Content ValidityThe measuring

instrument must be appropriate for obtaining the

information desired.

Criterion ValidityCriterion validity (or

criterion-related validity) measures

how well one measure predicts an outcome for another

measure.

Construct ValidityConstruct validity is used to determine

how well a test measures what it is

supposed to measure.

Content validity is the extent to which the elements within a measurement

procedure are relevant and representative of the construct (an

example of construct: “satisfaction with restaurant service”). Review of literature

supports to make content validity.

It is also called as concrete validity.The following example helps to understand:

A graduate student takes the GMAT. The GMAT has been shown as an effective

tool (i.e. it has criterion validity) for predicting how well a student will

perform in graduate studies.

Construct validity is usually verified by comparing the test to other tests that measure similar qualities to see how

highly correlated the two measures are.

Validity refers to

the truthfulness of findings.

The major concern of validity is:

“Whether the research truly

measures what it was intended for.”

If an instrument (for example,

questionnaires or scale design etc.) does not measure

accurately what it is supposed to

measure, there is no reasons to use it.

Sources of measurement problems


Respondents may not understand the question.

Respondents may not remember the necessary information.

Respondents may bound with code of conducts.

Poor choice of measurement scale

Sampling


The Issues of Sampling

Assigned for self work and intensive discussion with

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