Designing effective tables Kostas Danis. Competency to be gained from this lecture Lay out data effectively in tables

Designing effective tables

Kostas Danis

Competency to be gained from this lecture

Lay out data effectively in tables

Key areas

• Essential rules when arranging a table• Common tables in field epidemiology

Communicating patterns and messages contained in your data

• Show the patterns inherent in the data• Focus attention on these patterns• Serve as a basis for narrative or

discussion• Lead observer to insight, discussion,

conclusions

Avoid visual puzzles in tables

• Poorly organized data• Series of complicated numbers• Important data obscured• Unnecessary frames, lines, coloring• Decoration

Basic table rules

Column headings

Data

Footnotes

Title

Row headings

Typical table layout with components

Making sure that a table is understandable without referral to other

material • Title

Person Time Place Content of cells (any measurement found in all

columns)

• Row and column headings Content of the row or column Any modifier applied to all cells of a row or column Unit of measurement Abbreviations, if necessary

• Eliminate acronyms, unless standard (eg.OR)• Avoid excessive use of capitals

Basic table rules

Using footnotes in a table

• Clarify points of potential ambiguity• Explain all:

Abbreviations Symbols Codes

• Note exclusions • Mention data source if applicable

Basic table rules

Table 2. Cases And Controls Among Customers at UMFS

Cases Controls TotalOR

(95%CI)

Swordfish 34 20 54 13.2 (5.3-33.0)

Paella 8 62 70 0.1 (0.01-0.95)

Chicken 12 23 35 1.0 (0.4-1.9)

Flan caramel 20 40 60 0.9 (0.2-2.9)

Crema catalan 10 22 32 0.3 (0.1-1.4)

Lemon tarte 0 80 120 -

Incomplete title

Absence of necessary footnotes

Excess use of capitals Acronyms

REVISED Table 2. Frequency of exposures among 42 cases of gastrointestinal illness and

82 controls by fish consumption, ”Uncle Mike’s Fish & Chips”, Berlin, 2005

ExposureCases*

n=42Controls

n=82Odds Ratio(95CI% †)

Swordfish 34 20 13 (5.3-33)

Paella 8 62 0.1 (0.0-0.9)

Chicken 12 23 1.0 (0.4-1.9)

Flan caramel 20 40 0.9 (0.2-2.9)

Crema catalan 10 22 0.3 (0.1-1.4)

Lemon tarte 0 80 Reference

* 2 cases were excluded† 95% Confidence Interval

*ASC Ehrenberg, J R Statis Soc A, 140(3):277-297, 1977

Suggestions for data arrangement in tables*

1. Round data to 2 meaningful figures2. Summarize rows and columns3. Compare numbers in columns 4. Arrange key data by magnitude5. Help the reader with easy table layout6. Align numbers by decimalures

Basic table rules

Table with excessive number of meaningful figures

Factor Cases RateRate Ratio pa

None 27451 2.345 1.000 Refb

A 34211 3.433 1.464 0.1011

B 11002 5.661 2.414 0.0133

C 5643 6.001 2.559 0.0005

a. p-value

b. Reference exposure category

Up to five meaningful figures

Rate ratios difficult to compare

1. Round data to 2 meaningful figures

Basic table rules

Rounding data in a table to 2 meaningful figures

Factor

Cases(1000s

) RateRate ratio p

None 27 2.3 1.0 Ref*

C 34 3.4 1.5 >0.100

A 11 5.7 2.4 <0.050

B 06 6.0 2.6 <0.001

a. p-value


2 meaningful figures

Rate ratios easier to compare

1. Round data to 2 meaningful figures

Basic table rules

Rounding tips

• Cut decimals for percentages, eg 56.78 %• Use of thousand dividers, eg 18,526• Round up measures of associations to 2 meaningful

figures: 2 decimals between 0-0.99 1 decimal between 1-9.9 0 decimals between 10-99 round to nearest 10 between 100-999ORs symmetrical around 1 on log scale134 same precision as 13.4 or 1.34 or 0.134

X

Rounding tips: p-values

Basic table rules

P-valueNumber of decimals Example

>0.10 2 0.21

<0.10-0.001 3 0.041

<0.001 3 p<0.001

Year M FBoth Sexes

1973 500 99 600

1970 580 87 670

1968 460 89 550

1966 260 71 330

Mean 430 86 520

Summary of the columns

Summary of the rows

2. Summarize rows and columns

Summarizing rows and columns with totals, averages or other statistics

Basic table rules

Compare numbers in columns

23 42 34 109 87 42 27 98 114 75

Difficult to compare numbers in rows

23 42 34

109 87 42 27 98

114 75

1st improvement: Right-justify numbers

vertically 2327

34424275

87 98109

114

2nd improvement: Sort numbers

3. Compare numbers in columns

Basic table rules

Organize data by magnitude

Exposure

Cases(1000

s) RateRate ratio Pa

A 11 2.9 1.3 > 0.100

B 06 9.9 4.3 < 0.001

C 34 5.4 2.3 > 0.100

None 27 2.3 1.0 Refb

4. Arrange key data by magnitude

a. p-value

b. Reference exposure category Basic table rules

Organize data by magnitude

Exposure

Cases(1000s

) RateRate ratio pa

B 6 9.9 4.3 < 0.010

C 34 5.4 2.3 < 0.050

A 11 2.9 1.3 > 0.001

None 27 2.3 1.0 Refb

a. p-value


4. Arrange key data by magnitude

Basic table rules

YearBothsexes Male Female

1973 600 500 99

1970 670 580 87

1968 550 460 89

1966 330 260 71

Spaced out table layout: Comparisons difficult for the reader

5. Help the reader with easy table layout

Basic table rules

YearBothsexes Male Female

1973 600 500 99

1970 670 580 87

1968 550 460 89

1966 330 260 71


Drawing columns and rows close together facilitates comparisons

Basic table rules

Intervening statistics: Separated numbers are harder to compare

Rate per 1000 (SE)

Year Male Female All

1993 83 78 80

2.3 2.2 1.9

1994 62 66 63

2.5 2.7 1.8

1995 58 54 56

2.1 2.0 1.7

1996 55 45 51

2.0 2.0 1.7


Basic table rules

Rate per 1000 (SE)

Year Male Female All

1993 83 (2.3) 78 (2.2) 80 (1.9)

1994 62 (2.5) 66 (2.7) 63 (1.8)

1995 58 (2.1) 54 (2.0) 56 (1.7)

1996 55 (2.0) 45 (2.0) 51 (1.7)

Moving and minimizing intervening numbers facilitates readability


Basic table rules

Rate per 1000a

Year M F All

1993 83 78 80

1994 62 66 63

1995 58 54 56

1996 55 45 51

a. Standard errors for all rates less than 5% of rate.

Remove intervening numbers entirely if consequence minimal


Basic table rules

Align columns by decimal

23 42 34

10.9 8.7 42 27 9.8 114 75

23.0 42.0 34.010.9 8.7

42.0 27.0

9.8 114.0

75.0

Keeping the zeros or not is a question of personal style

6. Align numbers by decimal

Basic table rules

More suggestions

1. Use one column for each of figures2. Use only horizontal lines between sections of

table3. Avoid redundant (duplicated) data4. Use landscape format to display more

information, if needed5. Merge tables that share the same

denominator, but do not mix data from different populations, denominators, indicators (medians/proportions)

Basic table rules

Table 1: Distribution of the Households (n=506) by per capita monthly income,

Place X, 20012Monthly income per

capita (Euros)

Number

(%)

Up to 500 268

(53.0)

501 – 1000 131

(25.94)

1001 – 2000 75

(14.82)

>2000 32

(6.31)

Place number and % in separate columns

Excessive use of formatting lines, vertical divider not needed

Text not aligned to the left

Proportions not rounded

REVISED

Table 1: Distribution of the households (n=506) by per capita monthly income,

Place X, 2012Monthly income

Per capita (Euros)

Numbe

r

Percentag

e

Up to 500 268 53

500-1,000 131 26

1,001-2,000 75 15

>2,000 32 6

Table 2- Baseline characteristics of parents/guardians and their children, vaccination

coverage survey, Greece, 2006

Common tables

Sex Number Percentage

Female 1,919 49.6

Male 1,949 50.4

Total 3,868 100

Redundant:

Proportion of females will indicate proportion of males

X

Table 4- Complete vaccination coverage of children by place of residence, vaccination coverage survey, Greece, 2006

Place of residence

n (weighted %) 95% CI

UrbanRural

1676 (65%)448 (58%)

63.2-67.552.5-61.3

Table 3- Complete vaccination coverage of children by maternal belief, vaccination coverage survey, Greece, 2006

n (weighted %) [95%CI]

Positive attitude of mother towards her child’s vaccinationNo

1993 (64.5) [62.2-70.5]

24 (52.3) [49.1-62.1]

Row heading takes more than one line-too wordy

Use one column for each figure

Consider landscape format

Merge tables with identical structrure

Use thousand dividers

Cut decimals from percentages

Explain 95%CI in a footnote

n % * 95% CI†

Place of residence

UrbanRural

1,676 448

6558

63-6752-61

Maternal attitude

PositiveNegative

1,99324

6552

62-7149-62

REVISEDTable 3- Complete vaccination coverage of children by selected characteristics, vaccination coverage survey,

Greece, 2006

* Weighted % allowing for clustering † 95% Confidence Interval

Table 2. Clinical characteristics of 102 cases of campylobacteriosis, Ireland, 2002

Characteristics Value

Total cases 102

Median age (years)Range (years)

FeverDiarrhoeaJoint pain

355-83

65 (65.6 %)102 (100 %)

4 (4.3)

HeadacheMuscle pain

Isolation of organism

12 (12.4%)4(4.4%)

Stool samples (5/93%)

Text must be alighned to the left

The table presents frequency of symmptoms

Quantitave variables/other info should not be here

Sort rows. Decreasing order

REVISED

Table 2. Frequency of clinical characteristics of 102 cases of campylobacteriosis, Ireland, 2002

Symptoms n %

Diarrhoea 102 100

Fever 65 66

Headache 12 13

Joint pain 4 4

Muscle pain

4 4

Arranging common types of tables in epidemiology

• Line listing• Two variable table• Complex table• Cohort study• Case-control study

Common tables

State Age1 Sex Days2 Dose

New York 02 M 03 1

California 03 M 03 1

Pennsylvania 06 M 03 1


Colorado 04 F 04 1


Kansas 02 F 05 1

Colorado 03 M 05 1

New York 03 F 05 1

North Carolina 04 F 05 1

Missouri 11 M 05 1

Pennsylvania 03 F 07 1

California 04 F 14 2



1. Age in months

* MMWR, 48 (27):577

2. Days from dose to symptom onset

Reported cases of intussusception among recipients of rotavirus vaccine, by state, United

States, 1998-1999*

a. Line listing

Common tables

New cases of primary and secondary syphilis by age group and sex, United States, 1989

Age group Cases (100’s)

(years) Male Female Total

14 0.4 1.9 2.3

15-19 17.4 27.9 44.3

20-24 51.4 53.9 100.3

25-29 53.4 42.9 96.3

30-34 55.4 31.9 86.3

35-44 50.4 19.9 69.3

45-54 21.4 49.9 26.3

55 11.4 13.9 13.3

Total 260.4 180.9 440.3

b. Two variable table

Common tables

Complex table

Children

Character Exp %(n=205)

Not exp %(n=8729) p

Gestational age (weeks) at birth

<25 5.8 14 0.04

25-29 18.0 19 NS

Birthweight (kg)

1.5 15 .0 15 NS

2.5 39 .0 43 NS

c. Complex table

Common tables

ate ham

did not ham

ill not ill

49 49 98

4 6 10

2x2 table for calculation of measure of effect

d. Cohort study

Tab. IV Fish consumption and gastro-intestinal illness among customers at ”Uncle Mike’s Fish & Chips”, Berlin, 2005

Ill Total Attack rate

Relativerisk

Ate fish 42 58 72% 9.3 (3.9-22)

Did not eat fish

5 64 8% Ref

Total 47 122 39%

d. Cohort study

2x2 table fo

r caclu

lations

Not for p

resentatio

n

Exposed

Exposure%

Res. a

Yes No RRc (95% CId)

n ARb n ARb

Type 1

Sub Type 1-A

( - )

Sub Type 1-B

( - )

Sub Type 1-C

( - )

Type 2 ( - )

Type 3 ( - )

Type 4:

a. Res. = Respondedc. RR = Risk Ratio

b. AR = Attack Rate – cases per ___d. 95% CI = 95% confidence interval of the RR

d. Cohort study

Risk of ______ by exposure, among #### residents of Place, time

Common tables

Exposed

Exposure n AR a RR b 95% CI c

Type or Level 3

Type or Level 2

Type or Level 1

None or Level 0 1.0 Referent

b. RR = Risk Ratio

c. 95% CI = 95% confidence interval of the RR

a. AR = Attack Rate – cases per ___

Risk of ______ by exposure, among #### residents of Place, time

d. Cohort study (reference group)

Common tables

Exposed

Not exposed

Cases Controls Odds ratio

Case control study

50 20 4 a b

50 80 c d

Total 100 100

Exposed % (n) a

Exposure Cases Controls OR b 95% CI c

Type 1 (n) (n) ( – )

Sub Type 1-A (n) (n) ( – )

Sub Type 1-B (n) (n) ( – )

Sub Type 1-C (n) (n) ( – )

Type 2 (n) (n) ( – )

Type 3 (n) (n) ( – )

c. 95% CI = 95% confidence interval of the OR

a. n = subjects responding b. OR = Odds Ratio

Exposures (%) among ### cases and ### controls, Place, Time

e. Case control study

Common tables

Table from a case control study

Table 5. Association between exposures and campylobacteriosis in case-control

study, Oslo, Norway, 1998. Univariate, matched analysis.

Exposure Cases Controls Odds 95% conf.

ratio interval

Eaten at pizza restaurant 9/37 12/70 1.8 0.62 - 5.0

Eaten at party 10/36 9/74 3.2 0.97 - 11

Eaten foods from deli 23/37 42/74 1.2 0.56 - 2.7

Eaten unpeeled fruits 19/37 54/74 0.27 0.10 - 0.78

Close contact with a case 7/35 2/72 13 1.5 - 110

Drank >4 glas of water per day 21/37 33/74 1.7 0.73 - 3.9

Customer of water company B 27/37 33/74 4.0 1.3 - 7.3

Food Specific Attack Rates, Outbreak of Salmonellosis, Prison X, Dover, Delaware,

September 1992

6.21.51.3 1.1

REVISED for oral presentationFood specific attack rates, outbreak of

Salmonellosis, prison X, Dover, Delaware, September 1992

Take home message

Design your table around the message that is contained in your data

Practical 1

Spot the errors of the following tables

2.3. Reported laboratory diagnosis methods for chronic and acute infections

Lab. method

anti-HCV anti-HCV+ RNA-HCV

RNA-HCV Data missin

g

Chronic cases

(n=10403)

4084 (40.3%)

2659(25.4%)

2057(20%)

1603 (15%)

Acute cases

(n=956)

383(40.4%)

260(27.3%)

199(21.2%)

114(12.4

%)

SmiNet database 2005-2011

Seroconversion could not be verified for the VHC acute cases.- Place acute and chronic vertically to facilitate

comparison- Round up proportions- Add thousand dividers

Reported laboratory diagnosis methods for chronic and acute HCV infections, SmiNet database 2005-2011

Seroconversion could not be verified for acute hepatitis C cases.

Information available among cases

Acute cases Chronic cases

n % n %

Anti HCV 4,084 40 383 40

Anti HCV + RNA 2,659 25 260 27

RNA HCV 2,057 20 199 21

Data missing 1,603 15 144 12

Total 10,403 100 956 100

- Vertical comparisons- Rounded proportions

- Thousand dividers

CMOs reporting procedures19/21 CMOs replied the questionnaire

Easy to apply case definitions?

Yes (Both chronic and acute)

Yes (Only chronic)

Yes (Only acute)

No

Replies (n=19) 9 (47.5%) 1 (5%) 0 9 (47.5%)

Reporting instructions

for labs

Report after confirmation by

imunoblot positive test

Report after any

antibody positive

test

Wait for RNA

confirmation test

Other

Replies (n=19)

12 (63%) 2 (10%) 1 (5%) 4 (21%)

- Two tables with identical structure- Incomplete title

Hepatitis C reporting procedures described by 19 of the 21 Chief Medical Officers (CMOs) surveyed, Sweden, 2012

Item Answers N %

Case definition easily applicable

For chronic and acute cases 9 47

For chronic cases only 1 5

For acute cases only 0 0

No 9 47

Reporting instruction for laboratory

After confirmation (Iblot) 12 63

After any antibody test 2 10

Wait for RNA 1 5

Other 4 21

Total 19 100

- Merged table- Time, place and person title

Sexually transmitted infections (STIs)• Main public health concern

• Prevention of STI transmission is a major PH challenge

Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England

New STI diagnoses

Year % Change

2009 2010 2011 2009-10 2010-11 2002-11

Chlamydia 189,356 189,314 186,196 0% -2% 135%

Gonorrhoea 16,144 16,835 20,965 4% 25% -13%

Syphilis* 2,851 2,650 2,915 -7% 10% 87%

Herpes** 27,536 29,794 31,154 8% 5% 81%

Warts** 77,845 75,415 76,071 -3% 1% 21%

Total*** 426,735 419,773 426,867 -2% 2% 49%

*Syphilis: primary, secondary & early latent **Anogenital herpes / warts

***Total includes diagnoses stated in the table, plus ‘Non-specific genital infection’, ‘Pelvic inflammatory disease & epididymitis’ and ‘Other new STI diagnoses’

Source: http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1215589015024 53

- Two parts in table: Values and changes- Footnote too small / detailed

- Heterogeneous content indicator-wise

Practical 2

Prepare dummy tables for a:•case-control study•cross-sectional study

Practical 2a

Prepare dummy tables for a:•case-control study to identify risk factors for Campylobacter infection•Exposures:

travel food consumption (chicken, lettuce) domestic animals

•Demographics

Practical 2b

Prepare dummy tables for a:•Sero-prevalence study to identify risk factors for West Nile virus infection•Exposures:

rural place of residence mosquito protection employment status

Exposed % (n) a

Exposure Cases Controls OR b 95% CI c

Age>medianFood (n) (n) ( – )

Chicken (n) (n) ( – )

Lettuce (n) (n) ( – )

Travel abroad (n) (n) ( – )

Domestic animal (n) (n) ( – )

c. 95% CI = 95% confidence interval of the OR

a. n = subjects responding b. OR = Odds Ratio

Exposures (%) among ### cases of campylobacter and ### controls, Place,

Time

Exposed

Exposure % P a PR b 95% CI c

Population size Urban Rural 1.0 Referent

Mosquito protection

Often Rarely Never 1.0 Referent

b. RR = Prevalence Ratio

c. 95% CI = 95% confidence interval of the RR

a. P = Prevalence– cases per ___

Prevalence of West Nile virus infection by exposure, among #### residents of

Place, time

Common tables

Group ERS

Group KLO

Group MGI

Group NHO

Group NEA

Group KLN

Day 1-2 Day 1-2 Day 1-2 Day 3-4 Day 3-4 Day 3-4

Factory Atada NDPH

13** 1245 53 3467 3462 2425

Factory Seuda 457 2351 6589 9i0 569 43§

Factory Desda 111 (56) 43 (96) 35 (97) 46 (53) 56 (75) 567 (42)

Factory Rioja 1 1 0 3

Mean age 23 34 23 45 23 32

Travel hours 64 45 56 678 89 890

H C AB level 67 70 890 4356 56 76

HIV + 54 56 678 567 890 9080

Primary school 345 34 45 e65 56 78

Secondary school 234 54 65 568 76 878

BACK-UP SLIDES

61

Results

• Number of cases submitted to USISSAge group

Type<1 1 to 4 5 to 14 15 to 44 45 to 64 65+ Total

A(H1N1) 2 4 1 6 5 7 25A(H3N2) 5 8 3 16 18 17 67A(unknown) 10 20 8 34 21 40 133B 2 0 4 2 8 3 19Total 19 32 16 58 52 67 244

Information hard to follow as table

62

Number of cases submitted to USISS, by age and virus, {Place},

{Time}

Data presented at as graph

Exposed Unexposed

Exposure Total Cases AR% Total Cases AR% RRConfidence

interval P

blood glucose monitoring 30 8 26.67 56 0 0.00 20.26 [3.18-∞] <0.001

diabetes mellitus 40 8 20 46 0 0.00 11.05 [1.71-∞] 0.003

insulin injection 25 6 24.00 61 2 3.28 7.32 [1.58-33.84] 0.003

chiropody 53 8 15.09 33 0 0.00 6.45 [1.01-∞.] 0.048

upper floor 57 8 14,04 29 0 0.00 5.62 [0.87-∞] 0.056

ground floor 43 1 2.33 43 7 16.28 0.14 [0.02-1.11] 0.058

urethral catheter 4 1 25.00 76 7 9.21 2.71 [0.43-17.06] 0.350

eye drops 10 1 10.00 73 7 9.59 1.04 [0.14-7.62] 1.000

sex 26 2 7.69 60 6 10.00 0.77 [0.17-3.56] 1.000

dialysis 1 0 0.00 78 8 10.26 0.00 [.-.] 1.000

63

Multivariable analysis: only blood glucose monitoring significant

Results

- Redundant stats

- Alignment- Decimals

- Neutral title

Exposed Unexposed

Exposure Total Cases AR% Total Cases AR%Relative

riskConfidence

interval

Glucose monitoring 30 8 27 56 0 0 20 3.2-∞

Diabetes mellitus 40 8 20 46 0 0 11 1.7-∞

Insulin injection 25 6 24 61 2 3 7.3 1.6-34

Chiropody 53 8 15 33 0 0 6.4 1.0-∞.

Upper floor 57 8 14 29 0 0 5.6 0.87-∞

Ground floor 43 1 2 43 7 16 0.14 0.0-1.1

Urethral catheter 4 1 25 76 7 9 2.7 0.43-17

Eye drops 10 1 10 73 7 10 1.0 0.14-7.6

Sex 26 2 7 60 6 10 0.77 0.17-3. 6

Dialysis 1 0 0 78 8 10 0.0 .-.

64Multivariable analysis: Only blood glucose

monitoring significant

Risk of hepatitis B according to selected exposures, nursing home, Saxony, Germany, 2011

- Full title- Rounding off

- Alignment- P values deleted

Documents

Designing effective tables Kostas Danis. Competency to be gained from this lecture Lay out data effectively in tables