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Data presentation. A guide to good tables. Marianne W. Zawitz zawitzm@ojp.usdoj.gov. Bureau of Justice Statistics October 11, 2000. Elements of a table. Bureau of Justice Statistics. Table 1. Number of widgets and gadgets by color. Number. Widgets. Color. Gadgets. Total. 14. Blue.
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Data presentation A guide to good tables Marianne W. Zawitz zawitzm@ojp.usdoj.gov Bureau of Justice Statistics October 11, 2000
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color { • Number • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 Stub • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color Header • Number • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color Spreader Head • Number • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number Datafield • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number Cell • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number Row • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number Column • Widgets • Color • Gadgets • Total • 14 • Blue • 20 • 6 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color Title • Number • Widgets • Color • Gadgets • Total • 14 • 6 • Blue • 20 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 * True color is aqua not green.
Elements of a table Bureau of Justice Statistics Table 1. Number of widgets and gadgets by color • Number • Widgets • Color • Gadgets • Total • 14 • 6 • Blue • 20 • 23 • Red • 28 • 5 • 3 • Green* • 18 • 15 Notes * True color is aqua not green.
to present 10 or fewer data points • to find exact numeric values • to make localized comparisons Use tables, when you need - Bureau of Justice Statistics
Tables have an architecture • Use the structure of the table to reinforce its purpose • Take advantage of how we learned to do math Bureau of Justice Statistics
327 483 123 42 7 18 327 483 123 42 7 18 Bureau of Justice Statistics
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Types of tables - • Exploratory tables • Resource tables • Presentation tables Bureau of Justice Statistics
Example of an exploratory table 12 and 13-14 15 16 17 18 19 20 21 under 1979 6.7 122 236 326.4 404 472.1 425 400.9 403.9 1980 6.7 126.3 251 319.4 400.8 457.5 429.9 399.6 407.4 1981 7.2 138.4 262.5 339.7 406 460.9 450.5 407 410.9 1982 6.8 128.5 266.6 336.9 420.9 471.6 465.8 443.5 432.1 1983 7.5 130.8 245.5 316.3 393.4 433.2 413.4 393.6 399.8 1984 7.4 141.2 267.1 336.5 414.8 468.7 433.6 392.4 410 1985 8.2 165.6 302.9 374.6 444.3 501.2 469.5 418.9 415 1986 7.2 166.9 297.3 388.7 476.4 560.5 508.9 484.3 468.6 1987 7.2 163.5 295.8 368.8 458.4 548.3 516.1 469.8 474 1988 9.3 180.1 343.9 435.5 541.2 634.8 558.5 509.9 497.1 1989 9.5 206.5 391.8 531.7 640.2 704.8 638 541.9 543.2 1990 8.9 221.2 416.7 553.9 661.8 756.3 632.3 546.5 521.4 1991 12.7 280.6 518.4 669.7 775.1 886.6 725.2 601.9 591.4 1992 13.9 316.5 559 724.1 802.9 920.1 777.6 651.5 610.8 Bureau of Justice Statistics
Resource table Number of Full-time Full-time State agencies employees sworn officers All States 18,769 921,978 663,535 Alabama 432 14,389 9,767 Alaska 69 1,884 1,254 Arizona 130 16,828 10,088 Arkansas 360 7,958 5,819 California 524 103,967 69,134 Colorado 247 14,002 9,896 Connecticut 129 10,319 8,525 Delaware 45 2,134 1,660 District of Columbia 3 4,651 3,909 Florida 385 60,808 37,395 Bureau of Justice Statistics
Presentation table Homicides of children under age 5 Relationshipwith child Percent of perpetrators Father 32% Acquaintance 30 Mother 28 Other family 6 Stranger 4 Bureau of Justice Statistics
Show the data • Reduce nondata ink • Avoid puzzles • Create a logical visual pattern • Use the same standards for verbal elements we use in graphics Tables should -- Bureau of Justice Statistics
Excess lines and marks make the data hard to see State Full-time employees Full-time sworn officers Number of agencies All States ................... 18,769 921,978 663,535 Alabama .................... 432 14,389 9,767 Alaska ........................ 69 1,884 1,254 Arizona ...................... 130 16,828 10,088 Arkansas ................... 360 7,958 5,819 California ................... 524 103,967 69,134 Colorado .................... 247 14,002 9,896 Connecticut ............... 129 10,319 8,525 Delaware .................... 45 2,134 1,660 District of Columbia . 3 4,651 3,909 Florida ....................... 385 60,808 37,395 Bureau of Justice Statistics
Without the lines the data are the focus of the table State Full-time employees Full-time sworn officers Number of agencies 18,769 921,978 663,535 All States 432 14,389 9,767 Alabama 69 1,884 1,254 Alaska 130 16,828 10,088 Arizona. 360 7,958 5,819 Arkansas 524 103,967 69,134 California 247 14,002 9,896 Colorado 129 10,319 8,525 Connecticut 45 2,134 1,660 Delaware 3 4,651 3,909 District of Columbia 385 60,808 37,395 Florida Bureau of Justice Statistics
They imply false precision(often they are not significant) • They pad the numbers making them bigger than they really are • Use only as many decimal places as needed to break a tie Keep decimal places to a minimum Bureau of Justice Statistics
With fewer decimal places, it is easier to read This table has too many decimal places Homicides of children under age 5 Homicides of children under age 5 Male perpetrators Male perpetrators Male victim 67.8697% Male victim 68 % Female victim 21.9989% Female victim 22 Female perpetrators Female perpetrators Male victim 7.7851% Male victim 8 Female victim 2.3463% Female victim 2 The numbers were different enough that decimal places were not needed Bureau of Justice Statistics
Reduce the data presented • Not present everything to show that it all adds up • Use only one of the two variables when presenting binary data Presentation tables should -- Bureau of Justice Statistics
Order the content according to how the data will be used • Presentation tables use rank order or another hierarchy-- Look to the numbers to carry out the ordering • Resource tables use alphabetical or reference order Bureau of Justice Statistics
Rank order in presentation tables reveals the structure of the data Homicides of children under age 5 Relationshipwith child Percent of perpetrators Father 32% Acquaintance 30 Mother 28 Other family 6 Stranger 4 Bureau of Justice Statistics
Order resource tables alphabetically or in another meaningful manner State Full-time employees Full-time sworn officers Number of agencies 18,769 921,978 663,535 All States 432 14,389 9,767 Alabama 69 1,884 1,254 Alaska 130 16,828 10,088 Arizona. 360 7,958 5,819 Arkansas 524 103,967 69,134 California 247 14,002 9,896 Colorado 129 10,319 8,525 Connecticut 45 2,134 1,660 Delaware 3 4,651 3,909 District of Columbia 385 60,808 37,395 Florida Bureau of Justice Statistics
make patterns and exceptions obvious at a glance • place numbers that are to be compared close to one another (in a column is best) • place summary data where it will be most useful Structure the table to -- Bureau of Justice Statistics
This structure makes it difficult to compare the same units 1990 1995 1996 ITEM Number Percent Number Percent Number Percent TYPES OF SUBSTANTIATED MALTREATMENT/1 Victims, total 690,658 (X) 970,285 (X) 969,018 (X) Neglect 338,770 49.1 507,015 52.3 500,032 51.6 Physical abuse 186,801 27 237,840 24.5 229,332 23.7 Sexual abuse 119,506 17.3 122,964 12.7 119,397 12.3 Emotional maltreatment 45,621 6.6 42,051 4.3 55,473 5.7 Medical Neglect (NA) (NA) 28,541 2.9 5,758 2.7 Other and unknown 61,477 8.9 157,819 16.3 175,613 18.1 Bureau of Justice Statistics
A revision puts the numbers that are to be compared close together TYPES OF SUBSTANTIATED MALTREATMENT/1 Number of victims Percent of all victims 1990 1995 1996 1990 1995 1996 -------------------------------------- -------------------------------------- Victims, total 690,658 970,285 969,018 100.0% 100.0% 100.0% Neglect 338,770 507,015 500,032 49.1 52.3 51.6 Physical abuse 186,801 237,840 229,332 27.0 24.5 23.7 Sexual abuse 119,506 122,964 119,397 17.3 12.7 12.3 Emotional maltreatment 45,621 42,051 55,473 6.6 4.3 5.7 Medical Neglect ... 28,541 25,758 2.9 2.7 Other and unknown 61,477 157,819 175,613 8.9 16.3 18.1 Bureau of Justice Statistics
A better way to restructure this table is to make the annual comparisons up and down Emotional Victims, Physical Sexual maltreat- Medical Other and Year total Neglect abuse abuse ment Neglect unknown Number 1990 690,658 338,770 186,801 119,506 45,621 ... 61,477 1995 970,285 507,015 237,840 122,964 42,051 28,541 157,819 1996 969,018 500,032 229,332 119,397 55,473 25,758 175,613 Percent 1990 100.0% 49.1% 27.0% 17.3% 6.6% ... 8.9% 1995 100.0 52.3 24.5 12.7 4.3 2.9 16.3 1996 100.0 51.6 23.7 12.3 5.7 2.7 18.1 Bureau of Justice Statistics
Notation should -- • be placed in the row labels and column headers if possible (otherwise they interfere with our ability to see the data) • not be numeric characters so they are not confused with the numbers Bureau of Justice Statistics
Notation in this table interferes with your ability to compare the numbers 1990 1995 1996 ITEM Number Percent Number Percent Number Percent TYPES OF SUBSTANTIATED MALTREATMENT/1 Victims, total 690,658 (X) 970,285 (X) 969,018 (X) Neglect 338,770 49.1 507,015 52.3 500,032 51.6 Physical abuse 186,801 27 237,840 24.5 229,332 23.7 Sexual abuse 119,506 17.3 122,964 12.7 119,397 12.3 Emotional maltreatment 45,621 6.6 42,051 4.3 55,473 5.7 Medical Neglect (NA) (NA) 28,541 2.9 5,758 2.7 Other and unknown 61,477 8.9 157,819 16.3 175,613 18.1 Bureau of Justice Statistics
Lighter notation conveys information without interfering TYPES OF SUBSTANTIATED MALTREATMENT/1 Number of victims Percent of all victims 1990 1995 1996 1990 1995 1996 -------------------------------------- -------------------------------------- Victims, total 690,658 970,285 969,018 100.0% 100.0% 100.0% Neglect 338,770 507,015 500,032 49.1 52.3 51.6 Physical abuse 186,801 237,840 229,332 27.0 24.5 23.7 Sexual abuse 119,506 122,964 119,397 17.3 12.7 12.3 Emotional maltreatment 45,621 42,051 55,473 6.6 4.3 5.7 Medical Neglect ... 28,541 25,758 ... 2.9 2.7 Other and unknown 61,477 157,819 175,613 8.9 16.3 18.1 Bureau of Justice Statistics
Avoid tables with many empty cells and don’t use notation for true 0’s Number Number Number State admitted executed removed All States -- -- -- Alabama -- -- -- Alaska -- -- -- Arizona -- -- -- Arkansas -- -- -- California -- -- -- Colorado -- -- -- Connecticut -- -- -- Delaware -- -- -- District of Columbia -- -- -- Florida -- -- -- Bureau of Justice Statistics -- see page 27.
have consistent labeling from table to table • indent the labels to show subdivisions (nesting) • create patterns with a line or half line skip every fifth entry in long lists Rows should -- Bureau of Justice Statistics
Label nesting shows relationships Homicides of children under age 5 Male perpetrators Male victim 68 % Female victim 22 Female perpetrators Male victim 8 Female victim 2
contain the same unit of measure • have labels that clearly identify what is measured (both numerator and denominator for rates or percentages) • avoid repetitious categories by spacing and grouping Columns should -- Bureau of Justice Statistics
Mixing units of analysis compares apples to oranges (or dogs to cats) Source: Statistical Abstracts of the United States Bureau of Justice Statistics
Avoid large gaps between the stub and first column Full-time Full-time State employees sworn officers All States 921,978 663,535 Alabama 14,389 9,767 Alaska 1,884 1,254 Arizona 16,828 10,088 Arkansas 7,958 5,819 California 103,967 69,134 Colorado 14,002 9,896 Connecticut 10,319 8,525 Delaware 2,134 1,660 District of Columbia 4,651 3,909 Florida 60,808 37,395 the grand canyon Bureau of Justice Statistics
A few additional thoughts • Use no more than 9 columns in a table • Add clues regarding the unit of analysis next to the first number (%, months, widgets, etc.) Bureau of Justice Statistics
Make all verbal tasks easy to understand • Do not use abbreviations • Avoid acronyms • Write all labels left to right • Use proper grammar Bureau of Justice Statistics
briefly describe the data presented • highlight the difference between this table and others in the first words • be long enough to inform but short enough not to bore Table titles should -- Bureau of Justice Statistics