Variables and Levels of Measurement EDU 6304 Edwin D. Bell

Instructional Objectives Identify the independent, intervening, dependent variable(s) of your action research project. Identify the levels of measurement of the data that you will use to answer the research question(s) about the relationship among your independent and dependent variable(s). Identify the appropriate type of statistics to analyze these data.

Vocabulary Objectives Variables = a changing quantity Variables Independent Variable = the quantity that you manipulate in in the action research Intervening Variable = the hypothetical quantity that helps explain the relationship among the independent and the dependent variables Dependent Variable = the variable that you measure in your action research Attribute is a particular value of the variable

Variables What are the independent, intervening, and dependent variables in your study? You will Illustrate their relationship to one another in your logic model.

Research Questions What are the research question(s) that you wish to answer about the relationship between the independent and the dependent variables? Given your use of triangulation in the study, what data will you collect to answer the research question(s)

Levels of Measurement The quantitative data that you collect will have different levels of measurement. There are four levels of measurement: nominal, ordinal, interval, and ratio

Nominal Level of Measurement The attribute of the value names the variable uniquely, e.g. the variable of gender has the unique attributes of male and female. There is no ordering of the attributes

Ordinal Level of Measurement The attributes can be rank-ordered in this level of measurement, but the distances between the attributes are not the same and consequently have no meaning, e.g. a survey item – Satisfaction with registration 1 (very dissatisfied), 2 (dissatisfied), 3 (neutral), 4 (satisfied), and 5 (very satisfied)

Interval Level of Measurement The distance between the attributes are the same so they can be interpreted, e.g., comparing the average growth of grade test scores for a 5 th grade class in with the average growth of grade test scores of the same teacher’s 5 th grade class in

Ratio Level of Measurement In this level of measurement there is an absolute zero that means something, e.g., the things that we can count – the number of students who were at or above grade level in the third grade for

Significance of Levels of Measurement It's important to recognize that there is a hierarchy implied in the level of measurement idea. At lower levels of measurement, assumptions tend to be less restrictive and data analyses tend to be less sensitive. At each level up the hierarchy, the current level includes all of the qualities of the one below it and adds something new. In general, it is desirable to have a higher level of measurement (e.g., interval or ratio) rather than a lower one (nominal or ordinal). (Trochim, 2006, par. 7)

Levels of Measurement and Statistical Tools Generally, parametric statistics, i.e., statistical tools that meet certain assumptions – normal distribution and sample size, are used with ratio and interval data.parametric statistics Generally, non-parametric statistics, which make fewer assumptions about the distribution of the data or the level of measurement of the data, are used with ordinal and nominal level data.non-parametric statistics

Assignment  Discuss this PowerPoint presentation in your work group.  In your class blog in BlackBoard, please identify the independent, intervening, and dependent variables in your action research; describe your research question(s); explain the levels of measurement of the data that you will collect to answer your research question(s); and identify the appropriate type of statistics to use in the analysis of the data.

Reference Trochim, W. M. K. (2006). Levels of Measurement, Research Methods Knowledge Base, Retrieved May 12, 2008 from aslevl.php aslevl.php