1. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Creating effective tables and charts Jane E. Miller, PhD

2. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Overview Criteria for effective tables and charts Guidelines for titles Anatomy of a table Anatomy of a chart Examples Practice writing sentences about table or chart

3. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Criteria for an effective table or chart Self-contained Succinct Organized to coordinate with associated narrative description

4. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Review: Information needed to report a number W’s (context) – When – Where – What – Who Identity of each variable – No “alphabet soup” acronyms! – Meaningful words or phrases for each variable Units or categories for all variables shown

5. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. What does “self-contained” mean? Each table and chart in your work should be self- contained. Without reference to the text, readers should be able to understand: – Purpose of that particular table or chart – Context (W’s) – Variables – Units or categories for all variables – Acronyms or symbols

6. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Test of “self-contained” A reader unfamiliar with your data or study should be able to point to any number in the table and be able to write a complete, correct sentence about that number, based solely on the information in that table and its notes. Population, number and percentage poor, by age group, United States, 2002 Age group (years) Number poor (1,000s) Total population (1,000s)% poor <18 12,13372,65316.7 18–64 18,861177,93410.6 65+ 3,57634,38510.4 Total34,570284,97212.1

7. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. What does “succinct” mean? Includes the information needed to address a specific question or set of related questions. Reduce clutter by avoiding – Unnecessary repetition of units within the table – Data labels on every point of the chart Remember: Charts are best for showing general level or shape, not precise values – Excessive number of digits and decimal places See chapter 4 of Writing about Numbers or Writing about Multivariate Analysis.

8. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Reducing duplicate labeling If every variable in the table is reported in dollars, don’t need to put “$” in every table cell – List the units in the title If an entire column is reported in percentage units, don’t need to put “%” in every cell. – List the units in the column label and convey “% of what”

9. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. What does “well-organized” mean? Structure should be easy to follow based on conventions for labeling and reading. Coordinated with prose description of table or chart. Usually means – Theoretical criteria – Empirical criteria (ascending or descending order) – See podcast on organizing data in tables and charts

10. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Writing an effective title Pertain specifically to content of that table or chart. – What question is that table/chart intended to answer? Include all “the W’s” – “What” is the topic of your table? Mention: Outcome (dependent) variables. Predictor (independent) variables. – “Who, when, where”? If source name is too long, put it in a footnote.

11. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Examples of titles Poor: “Descriptive statistics” – Way too general. Omits information about the topic, context, and types of statistics. Better: “Poverty patterns” – Identifies the dependent variable (poverty), but doesn’t convey what patterns (comparisons) are presented. – Among who? When? Where? – What are the units for each of the variables reported in the table? Best: “Number and percentage poor by age group, United States, 2002” – Identifies dependent and independent variables, context,and units.

12. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Anatomy of a table *Footnote (i.e., source of data, definition of terms, acronyms)

13. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Check: W’s: Who, what, when, where? Check: Units or categories for all variables shown? Note: “Poor”: family income below the federal poverty threshold for a family of given size and age composition. Source: Proctor and Dalaker. 2003. “Poverty in the United States: 2002.” Current Population Reports. P60–222. Washington, DC: US Government Printing Office. Population, number and percentage poor, by age group, United States, 2002 Age group (years) Number poor (1,000s) Total population (1,000s)% poor <18 12,13372,65316.7 18–64 18,861177,93410.6 65+ 3,57634,38510.4 Total34,570284,97212.1

14. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Anatomy of a pie chart Composition of a categorical variable Categories are identified in the legend Units in the data labels W’s in the title

15. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Anatomy of a simple bar chart Bivariate association between – a categorical independent variable on the x-axis, – a continuous dependent variable on the y-axis. Variables are identified on the axes, along with units (y-axis) or categories (x-axis). Note that categories are sorted in descending order of the value of the dependent variable, facilitating a well- organized written description.

16. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Anatomy of a multiple-line chart Three-way association between one continuous and one categorical IV and a continuous DV. The dependent variable and its units are on the y-axis. The continuous IV and its units are on the x-axis. The categorical IV is labeled in the legend.

17. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Range of values of independent variables Choose range of values for continuous independent variables that fit the topic and data. E.g., in model of birth weight: – Mother’s age at child’s birth plotted from 15 to 45 years of age. Corresponds with reproductive age range for women. – Income/poverty ratio (IPR) plotted from 0.0 to 5.0. Range that captures most of the observed values in the data set used to estimate the model.

18. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Writing sentences about a a table or chart Use title, labels, and footnotes to identify – The W’s – Units of measurement The contents of a specific table cell are identified by the labels on the pertinent rows and columns. The meaning of a specific point on a chart is identified by the pertinent axis labels and legend.

19. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Population, number and percentage poor, by age group, United States, 2002 Age group (years) Number poor (1,000s) Total population (1,000s)% poor <18 12,13372,65316.7 18–64 18,861177,93410.6 65+ 3,57634,38510.4 Total34,570284,97212.1 For the number in the green (underlined) cell, the row label (yellow) identifies the age group, the column label (blue) identifies the concept being measured and its units, and the table title identifies the W’s. “There were more than 12 million poor children (<18 years) in the United States in 2002.”

20. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Check: Self-contained pie chart? Write a sentence about the blue slice. “In 2004, 16% of 4 year- olds in the US were obese.” Check: Identify the – category in the legend, – units in the data labels, – W’s in the title.

21. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Check: Self-contained bar chart? Describe transpiration under the bright light condition. “The bright light condition resulted in the second highest rate of transpiration (5 ml/ m 2 /30 minutes). Only the fan (wind) condition yielded faster transpiration (8 ml/m 2 /30 minutes).” Check: – Concepts and units on the axes and footnote – W’s in the title – Rank order (direction)

22. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Summary Design your tables and charts to be – Self-contained – Succinct – Organized to coordinate with associated narrative description Follow standard conventions for anatomy of tables and charts

23. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Suggested resources Chapters 4, 6, and 7 in Miller, J. E. 2004. The Chicago Guide to Writing about Numbers OR Chapters 4, 5, and 6 in Miller, J. E. 2013. The Chicago Guide to Writing about Multivariate Analysis, 2nd Edition. Miller, J. E. 2007. “Organizing Data in Tables and Charts: Different Criteria for Different Tasks.” Teaching Statistics 29 (3): 98–101. – And related podcast

24. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Suggested practice exercises Study guide to The Chicago Guide to Writing about Multivariate Analysis, 2nd Edition. – Problem sets for Chapter 5: questions 2, 5 and 7 Chapter 6: questions 2, 3, and 4 – Suggested course extensions for Chapter 5 – “Reviewing” exercise #3 – “Applying statistics” exercise #3 – “Writing and revising” exercises #3 and 4 Chapter 6 – “Reviewing” exercises #1 and 2 – “Applying statistics” exercises #1 and 2 – “Writing and revising” exercise #3

25. The Chicago Guide to Writing about Multivariate Analysis, 2 nd edition. Contact information Jane E. Miller, PhD jmiller@ifh.rutgers.edu Online materials available at http://press.uchicago.edu/books/miller/multivariate/index.html