1. Politics, Power, and Purpose: An Orientation to Political Science. Jay Steinmetz.
Read Chapter 1, “So what about Political Science?” This section explains the discipline, causation, and independent and dependent variables.
2. Introduction to Comparative Government and Politics. Dino Bozonelos, Julia Wendt, & Masahiro Omae.
Read “The Scientific Method.” This section explains the literature review, hypotheses, and independent and dependent variables.
3. Introduction to Political Science Research Methods. Josh Franco, Charlotte Lee, Kau Vue, Dino Bozonelos, Masahiro Omae, and Steven Cauchon.
Read Section 5.2 – Operationalization, p. 82-83; and Section 5.3: Measurement, p. 85-88 in text. These sections explain the term operationalization and different ways to measure variables.
This guidance from Univ. of Southern California can be helpful when writing the methods section of your paper:
Organizing Your Social Sciences Research Paper: Methodology
Additionally, here are some resources that can be helpful when thinking about the types of data you would want for this type of paper.