Lecture 7 Data Analysis: Quantitative, Qualitative, and Mixed Analysis

Gang He

April 27, 2024

Recap lecture 6

  • Data sources
  • Statistical data
  • Survey
  • Interview
  • Evaluation project consultation

Today’s agenda

  • Data analysis
  • Qualitative methods
  • Quantitative methods
  • Visualization
  • Story telling
  • Case: NYC G&T Program

Qualitative data

Primary purpose Methods
Enumerative Classical Content Analysis; Word count; Cultural domain analysis; Ethnographic decision models
Descriptive Matrix displays; Timelines; Concept maps/mind maps; Template/framework analysis
Hermeneutic Thematic analysis; Constant comparative method; Thematic narrative analysis; Framework analysis; Discourse analysis; Qualitative content analysis
Explannatory Qualitative comparative analysis; Process tracing

Coding and categorizing

Matrix displays

I have two kinds of problems: the urgent and the important. The urgent are not important, and the important are never urgent.

— Dwight D. Eisenhower

Delphi method/technique

Word counting

  • 2,406: Number of words in President Obama’s inaugural speech
  • 4: Number of times the president said “crisis”
  • 3: Number of times he said “economy”
  • 2: Number of times he said “war”
  • 67: Number of times he said “our”
  • 2: Number of times he said “my”
  • 1: Number of times he said “change”
  • 11: Number of times he said “new”

Discuss the limitations of word counting

Mindmap

Descriptive statistics

  • Distribution
  • Measures of central tendency
    • Mean
    • Median
    • Mode
  • Measures of variability
    • Range
    • Standard deviation
    • Variance
    • Interquartile range

Statistical tests

R squared

“The proportion of the variation in the dependent variable that is predictable from the independent variable(s).”

\(R^2\) does not indicate whether:

  • the independent variables are a cause of the changes in the dependent variable;
  • omitted-variable bias exists;
  • the correct regression was used;
  • the most appropriate set of independent variables has been chosen;
  • there is collinearity present in the data on the explanatory variables;
  • the model might be improved by using transformed versions of the existing set of independent variables;
  • there are enough data points to make a solid conclusion.

Summary of statistics


United States China Germany
Est. (Std. Err.) Est. (Std. Err.) Est. (Std. Err.)
(Intercept) 15 (1.04)*** 18 (1.58)*** 12 (0.96)***
log(cum_capacity_kw) -0.44 (0.045)*** -0.57 (0.070)*** -0.33 (0.042)***
log(price_si) 0.15 (0.058)* 0.23 (0.079) 0.21 (0.054)

Asterisks indicate the level of significance: *5%; **1%; ***0.1%.

Statiscal significance

p value: “The lower the p-value is, the lower the probability of getting that result if the null hypothesis were true.”

Stories

  • Data story
  • Method story
  • Pattens and trends
  • Organization and instution vision, mission, and efforts
  • Motivate changes

Climate Strips

Duck curve

Story

Hans Rosling, Data Visulization, and Storytelling

References

Benjamin, Daniel J., James O. Berger, Magnus Johannesson, Brian A. Nosek, E.-J. Wagenmakers, Richard Berk, Kenneth A. Bollen, et al. 2018. “Redefine Statistical Significance.” Nature Human Behaviour 2 (1): 6–10. https://doi.org/10.1038/s41562-017-0189-z.
Dodds, Peter Sheridan, Kameron Decker Harris, Isabel M. Kloumann, Catherine A. Bliss, and Christopher M. Danforth. 2011. “Temporal Patterns of Happiness and Information in a Global Social Network: Hedonometrics and Twitter.” PLOS ONE 6 (12): e26752. https://doi.org/10.1371/journal.pone.0026752.
Helveston, John Paul, Gang He, and Michael R. Davidson. 2022. “Quantifying the Cost Savings of Global Solar Photovoltaic Supply Chains.” Nature 612 (7938): 83–87. https://doi.org/10.1038/s41586-022-05316-6.
Leek, Jeff, Blakeley B. McShane, Andrew Gelman, David Colquhoun, Michèle B. Nuijten, and Steven N. Goodman. 2017. “Five Ways to Fix Statistics.” Nature 551 (7682): 557–59. https://doi.org/10.1038/d41586-017-07522-z.
Newcomer, Kathryn E., Harry P. Hatry, and Joseph S. Wholey. 2015. Handbook of Practical Program Evaluation. 4th edition. San Francisco: Jossey-Bass.