What Is Measurement? - SAGE Publications Inc

1 1 What Is Measurement? OverviewThis chapter covers the basics of measurement . The chapter aims to provideunderstanding of measurement and measure development procedures cur-rently discussed in the literature. measurement error is introduced, and thesteps in the measure development process and empirical procedures to assesserror are described. The chapter uses many examples based on data to illus-trate measurement issues and procedures. Treatment of the material is at anintuitive, nuts-and-bolts level with numerous illustrations.

2 The chapter is not intended to be a statistics primer; rather, it providessufficient bases from which to seek out more advanced treatment of empiri-cal procedures. It should be noted that many issues are involved in usingappropriately the statistical techniques discussed here. The discussion in thischapter aims to provide an introduction to specific statistical techniques, andthe references cited here provide direction for in-depth Is measurement Error? measurement is essential to empirical research.

3 Typically, a method used tocollect data involves measuring many things. Understanding how any onething is measured is central to understanding the entire research measurement has been defined as rules for assigning numbers toobjects in such a way as to represent quantities of attributes ( , Nunnally,1978, p. 3). measurement consists of rules for assigning symbols to 1/10/2005 2:51 PM Page 1so as to (1) represent quantities of attributes numerically (scaling) or(2) define whether the objects fall in the same or different categories withrespect to a given attribute (classification) (Nunnally & Bernstein, 1994,p.)

4 3).1 The attributes of objects, as well as people and events, are the under-lying concepts that need to be measured. This element of the definition ofmeasurement highlights the importance of finding the most appropriateattributes to study in a research area. This element also emphasizes under-standing what these attributes really mean, that is, fully understanding theunderlying concepts being measured. Rules refer to everything that needs tobe done to measure something, whether measuring brain activity, attitudetoward an object, organizational emphasis on research and development, orstock market performance.

5 Therefore, these rules include a range of thingsthat occur during the data collection process, such as how questions areworded and how a measure is administered. Numbers are central to the def-inition of measurement for several reasons: (a) Numbers are standardized andallow communication in science, (b) numbers can be subjected to statisticalanalyses, and (c) numbers are precise. But underneath the fa ade of precise,analyzable, standardized numbers is the issue of accuracy and very idea of scientific measurement presumes that there is a thingbeing measured ( , an underlying concept).

6 A concept and its measurementcan be distinguished. A measure of a concept is not the concept itself, butone of several possible error-filled ways of measuring distinction canbe drawn between conceptual and operational definitions of conceptual definition describes a concept in terms of other concepts(Kerlinger, 1986; Nunnally, 1978). For instance, stock market performanceis an abstract notion in people s minds. It can be defined conceptually interms of growth in value of stocks; that is, by using other concepts such asvalue and growth.

7 An operational definition describes the operations thatneed to be performed to measure a concept (Kerlinger, 1986; Nunnally,1978). An operational definition is akin to rules in the definition of mea-surement discussed earlier in the chapter, and refers to everything that needsto be done to measure something. The Dow Jones average is one measureof stock market performance. This operational definition involves trackingthe stock value of a specific set of companies.

8 It is by no means a perfectmeasure of stock market performance. It is one error-filled way of measur-ing the concept of stock market term constructis used to refer to a concept that is specifically definedfor scientific study (Kerlinger, 1986). In Webster s New World Dictionary,constructmeans to build, form or devise. This physical meaning of theword constructis similar to the scientific meaning: Constructs are concepts2 measurement Error and Research 1/10/2005 2:51 PM Page 2devised or built to meet scientific specifications.

9 These specifications includeprecisely defining the construct, elaborating on what it means, and relatingit to existing research. Words that are acceptable for daily conversationwould not fit the specifications for science in terms of clear and precisedefinitions. I am going to study what people think of catastrophic events is a descriptive statement that may be acceptable at the preliminary stagesof research. But several concepts in this statement need precise description,such as think of, which may separate into several constructs, and catas-trophe, which has to be distinguished from other descriptors of explanations are essentially words, and some of these words relateto concepts.

10 Constructs are words devised for scientific science,though, these words need to be used carefully and defined measuring something, error is any deviation from the true value,whether it is the true value of the amount of cola consumed in a period of time,the level of extroversion, or the degree of job this truevalue is rarely known, particularly when measuring psychological variables,this hypothetical notion is useful to understand measurement error inherent inscientific research.