Discussion Follow up question

  

Assignment Question: Having in mind your study's main IV and DV, how would you operationalize those variables (review my post below)?

The study’s research question is: Is obesity (IV) associated with diabetes risk (DV) among Americans aged 35-45?

Dear student, let’s discuss Variables’ Operationalization and levels of measurement (Brunette, Nelson, & FOCUS Workgroup, n.d.; Gray, Williamson, Karp, & Dalphin, 2007; UTHealth, n.d.):

Types of variables: Operationalization and levels of measurement (Hammond, Malec, Nick, & Buschbacher, 2015):

Independent (IV – factor, exposure)

Dependent (DV - dependent on IV– outcome, disease)

Categorical (nonparametric)

Numerical (parametric)

A) Categorical variables: qualitative or discrete: nominal, dichotomous, and ordinal

1) Nominal (dichotomous (binary) or categorical) or 2) Ordinal – categories, levels, and rankings.

1. Nominal – variable is mutually exclusive and exhaustive; no intrinsic order between categories.

Dichotomous (binary): only two levels or categories:  Examples: sex: 1. Male, 0. Female; 1. Pass, 0. Fail;

Categorical: More than two levels or categories

Examples: Marital status: 1. Single; 2. Married; 3. Divorced; 4. Widowed

Blood type: 1. A, 2. B. 3. AB, 4.O

2. Ordinal – naturally ranked; ordered differences: low, medium, and high. Likert scales.

Examples: pain level (1. mild, 2. moderate, 3. severe); educational level (1. high school, 2. undergraduate, 3. graduate).

B) Numerical variables: quantitative (discrete – countable number of values; or continuous – any value in a range of values): interval or ratio:

3. Interval – distance between intervals are constant with absolute value.

Examples: temperature F and C – has intervals of degrees; IQ scores; weight.

4. Ratio – highest degree in precision and accuracy including measurement on a scale with a meaningful zero; units of equal interval and magnitude in ranked order.

Example: BMI (ratio of weight /height); age, blood pressure; time.

References

Brunette, K., Nelson, A., & FOCUS Workgroup (n.d.). Data analysis basics: Variables and distribution

Focus on Field Epidemiology, 3(5), 1-6. Retrieved from

https://nciph.sph.unc.edu/focus/vol3/issue5/3-5DataBasics_issue.pdf 

Hammond, F. M., Malec., J. F., Nick, T. G., & Buschbacher, R. M. (Eds.). (2015). Part II:

Statistics. Types of data. Handbook for clinical research: Design, statistics, and

implementation (p.79-83). New York, NY: Demons Medical Publishing, LLC.

Gray, P. S., Williamson, J. B., Karp, D. A., & Dalphin, J. R. (2007). Measurement. The research

imagination: An introduction to qualitative and quantitative methods (pp. 59-60). New York, NY:

Cambridge University Press.

UTHealth. (n.d.) Biostatistics for the clinician. Lesson 1.2.: Variables and measures.

Retrieved from https://www.uth.tmc.edu/uth_orgs/educ_dev/oser/L1_2.HTM