Chap-011测量.ppt

Chapter 11 Measurement Learning Objectives Understand . . . The distinction between measuring objects, properties, and indicants of properties. The similarities and differences between the four scale types used in measurement and when each is used. The four major sources of measurement error. The criteria for evaluating good measurement. PulsePoint: Research Revelation Why Measurement Is Important Measurement Characteristics of Measurement Levels of Measurement Types of Scales Nominal Scales Mutually exclusive and collectively exhaustive categories Exhibits the classification characteristic only Levels of Measurement Ordinal Scales Characteristics of nominal scale plus an indication of order Implies statement of greater than and less than Levels of Measurement Interval Scales Characteristics of nominal and ordinal scales plus the concept of equality of interval. Equal distance exists between numbers Levels of Measurement Ratio Scales Characteristics of previous scales plus an absolute zero point Examples Weight Height Number of children Moving from Investigative to Measurement Questions Sources of Error Evaluating Measurement Tools Validity Determinants Increasing Content Validity Validity Determinants Increasing Construct Validity Validity Determinants Judging Criterion Validity Understanding Validity and Reliability Reliability Estimates Reliability Estimates Reliability Estimates Reliability Estimates Practicality Key Terms Internal validity Interval scale Mapping rules Measurement Nominal scale Objects Ordinal scale Practicality Properties Ratio scale Reliability Equivalence Internal consistency Stability Validity Construct Contents Criterion-related This chapter introduces the concept of measurement, the four scale types, the major sources of error and criteria for evaluating good measurement. What are the characteristics of a good measurement tool? A tool should be an accurate indicator of what one needs to measure. It should be easy and efficie