Research Design & Scales of Measurement

Research process:

1) ask research question(s)

2) develop hypotheses

3) collect the data

4) analyze the data

5) evaluate the hypotheses

Asking research questions

Developing hypotheses

Collecting data

Populations, samples, and sampling:

Population Sample Sample type
pregnant women  every other pregnant woman at 3 Tacoma clinics  
Fortune 500 Fortune 500 cos. in WA  
adults in U.S. random sample of adults in households w/ telephones  
Superfund sites 65 largest sites in U.S.  

  Variables and measurement

Scales/levels of measurement

nominal - values indicate qualitatively different kinds

  • quantitative var. = ordinal or interval var.



    ordinal - values indicate ordered categories

    interval/ratio - degree of distance/difference between values can be specified

    Warning: be careful w/ numeric coding of nominal and ordinal scale data!

    Scales of measurement form a hierarchy:




    scale key feature comparisons betw. values
    interval distance different? which larger? how much larger?
    ordinal order different? which larger?
    nominal quality different?



    Part 2:

    Data collection methods

    More on measurement


    hypotheses are predictions about the value of a particular variable or relationships between variables

    independent variable = explanatory variable

    dependent variable = response/outcome variable

    Research design

    Miscellaneous terms