Tabular Display of Data Prepared by: Gary Klass

Data Presentation Standards “Graphical Excellence” -- Edward Tufte well-designed presentation of data of substance, statistics and design complex ideas communicated with clarity, precision and efficiency the greatest number of ideas in the shortest time with the least ink in the smallest space. Best example: Baseball statistics

Defense presentation at John Gotti trial:

Meaningful Data Count Divide Compare

Meaningful Data (contd.) Use rates, ratios and per capita measures rather than aggregate totals. Two time points are better than one. –Show change over a meaningful time period. (5 year change rather than annual change ). –Multi-year trends are best presented in time series charts rather than tables. Show the source of the data

Rates and Ratios

Two times points are better

Bad Tabular Display

Draw Conclusions from Meaningful Comparisons One year changes in crime rates are not very meaningful Rates (and averages) tell more than counts (crimes rates, not crime counts)

Unambiguous Data Each number in a table should have a precise meaning. –Use titles, headings, and notes to clearly define the data. Be precise when using rates and ratios –Clearly define the numerator and denominator of the measures Be clear about percent change, net percentage change. –Abortion rate vs. Abortion ratio –% of poor vs. the % that are poor –Net change vs. % percentage change

Unambiguous Data Change in Teenage Birth Rates: White 6.7% Black-4.9 Asian-1.8 Hispanic 3.7 Source: Statistical Abstract 2000, table 85

Efficiency Data can be quickly interpreted by the reader. –Sort data on the most meaningful variable –Time always left to right –Similar data goes down the columns –Highlight important comparisons –Don’t force comparisons between two different tables –Consistent formatting across tables

Do not sort alphabetically

Sort data….

Sorting data by least meaningful variable

Time goes left to right……………….

Variables define the columns

Variables define columns………

Highlight critical comparisons….

Highlighting Comparisons

Excel skills Combine cells for title, use word wrap Adjust cell widths Sort data Use formulas and copy formulas Do not use too many fonts Decimal places: 2 significant digits Horizontal borders Copy image to Word