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Designing effective tables

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Title: Designing effective tables


1

  • Designing effective tables
  • Kostas Danis

2
Competency to be gained from this lecture
  • Lay out data effectively in tables

3
Key areas
  • Essential rules when arranging a table
  • Common tables in field epidemiology

4
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

5
Avoid visual puzzles in tables
  • Poorly organized data
  • Series of complicated numbers
  • Important data obscured
  • Unnecessary frames, lines, coloring
  • Decoration

Basic table rules
6
Typical table layout with components
Title
Column headings
Data
Row headings
Footnotes
7
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
8
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
9
Table 2. Cases And Controls Among Customers at
UMFS
Incomplete title
Acronyms
Excess use of capitals
Cases Controls Total OR (95CI)
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 -
Absence of necessary footnotes
10
REVISED Table 2. Frequency of exposures among
42 cases of gastrointestinal illness and 82
controls by fish consumption, Uncle Mikes Fish
Chips, Berlin, 2005
Exposure Cases n42 Controls n82 Odds 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
11
Suggestions for data arrangement in tables
  1. Round data to 2 meaningful figures
  2. Summarize rows and columns
  3. Compare numbers in columns
  4. Arrange key data by magnitude
  5. Help the reader with easy table layout
  6. Align numbers by decimalures

Basic table rules
ASC Ehrenberg, J R Statis Soc A, 140(3)277-297,
1977
12
Table with excessive number of meaningful figures
1. Round data to 2 meaningful figures
Factor Cases Rate Rate 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
Up to five meaningful figures
Rate ratios difficult to compare
a. p-value
b. Reference exposure category
Basic table rules
13
Rounding data in a table to 2 meaningful figures
1. Round data to 2 meaningful figures
Factor Cases (1000s) Rate Rate ratio p
None 27 2.3 1.0 Ref
C 34 3.4 1.5 gt0.100
A 11 5.7 2.4 lt0.050
B 06 6.0 2.6 lt0.001
2 meaningful figures
Rate ratios easier to compare
a. p-value
b. Reference exposure category
Basic table rules
14
Rounding tips
X
  • 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 100-999
  • ORs symmetrical around 1 on log scale
  • 134 same precision as 13.4 or 1.34 or 0.134

15
Rounding tips p-values
P-value Number of decimals Example
gt0.10 2 0.21
lt0.10-0.001 3 0.041
lt0.001 3 plt0.001
Basic table rules
16
Summarizing rows and columns with totals,
averages or other statistics
2. Summarize rows and columns
Year M F Both Sexes
1973 500 99 600
1970 580 87 670
1968 460 89 550
1966 260 71 330
Mean 430 86 520
Basic table rules
17
Compare numbers in columns
3. Compare numbers in columns
Difficult to compare numbers in rows
23 42 34 109 87 42 27 98 114 75
Basic table rules
18
Organize data by magnitude
4. Arrange key data by magnitude
Exposure Cases (1000s) Rate Rate ratio Pa
A 11 2.9 1.3 gt 0.100
B 06 9.9 4.3 lt 0.001
C 34 5.4 2.3 gt 0.100
None 27 2.3 1.0 Refb
a. p-value
b. Reference exposure category
Basic table rules
19
Organize data by magnitude
4. Arrange key data by magnitude
Exposure Cases (1000s) Rate Rate ratio pa
B 6 9.9 4.3 lt 0.010
C 34 5.4 2.3 lt 0.050
A 11 2.9 1.3 gt 0.001
None 27 2.3 1.0 Refb
a. p-value
b. Reference exposure category
Basic table rules
20
Spaced out table layout Comparisons difficult
for the reader
5. Help the reader with easy table layout
Year Both sexes Male Female
1973 600 500 99
1970 670 580 87
1968 550 460 89
1966 330 260 71
Basic table rules
21
Drawing columns and rows close together
facilitates comparisons
5. Help the reader with easy table layout
Year Both sexes Male Female
1973 600 500 99
1970 670 580 87
1968 550 460 89
1966 330 260 71
Basic table rules
22
Intervening statistics Separated numbers are
harder to compare
5. Help the reader with easy table layout
Rate per 1000 (SE) Rate per 1000 (SE) 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
23
Moving and minimizing intervening numbers
facilitates readability
5. Help the reader with easy table layout
Rate per 1000 (SE) Rate per 1000 (SE) Rate per 1000 (SE) Rate per 1000 (SE) Rate per 1000 (SE) Rate per 1000 (SE)
Year Male Male Female Female All 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)
Basic table rules
24
Remove intervening numbers entirely if
consequence minimal
5. Help the reader with easy table layout
Rate per 1000a Rate per 1000a 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.
Basic table rules
25
Align columns by decimal
Difficult to compare numbers in rows
6. Align numbers by decimal
Keeping the zeros or not is a question of
personal style
23 42 34 10.9 8.7 42 27 9.8 114 75
23.0 42.0 34.0 10.9 8.7 42.0 27.0 9.8
114.0 75.0
Basic table rules
26
More suggestions
  1. Use one column for each of figures
  2. Use only horizontal lines between sections of
    table
  3. Avoid redundant (duplicated) data
  4. Use landscape format to display more information,
    if needed
  5. Merge tables that share the same denominator, but
    do not mix data from different populations,
    denominators, indicators (medians/proportions)

Basic table rules
27
Table 1 Distribution of the Households (n506)
by per capita monthly income, Place X, 20012
Monthly income per capita (Euros) Number ()
Up to 500 268 (53.0)
501 1000 131 (25.94)
1001 2000 75 (14.82)
gt2000 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
28
REVISED Table 1 Distribution of the households
(n506) by per capita monthly income, Place X,
2012
Monthly income Per capita (Euros) Number Percentage
Up to 500 268 53
500-1,000 131 26
1,001-2,000 75 15
gt2,000 32 6
29
Table 2- Baseline characteristics of
parents/guardians and their children, vaccination
coverage survey, Greece, 2006
Sex Number Percentage
Female 1,919 49.6
Male 1,949 50.4
Total 3,868 100
X
Redundant Proportion of females will indicate
proportion of males
Common tables
30
Table 4- Complete vaccination coverage of
children by place of residence, vaccination
coverage survey, Greece, 2006
Table 3- Complete vaccination coverage of
children by maternal belief, vaccination coverage
survey, Greece, 2006
Row heading takes more than one line-too
wordy Use one column for each figure Consider
landscape format
n (weighted ) 95CI
Positive attitude of mother towards her childs vaccination No 1993 (64.5) 62.2-70.5 24 (52.3) 49.1-62.1
Merge tables with identical structrure
Use thousand dividers Cut decimals from
percentages Explain 95CI in a footnote
Place of residence n (weighted ) 95 CI
Urban Rural 1676 (65) 448 (58) 63.2-67.5 52.5-61.3
31
REVISED Table 3- Complete vaccination coverage of
children by selected characteristics, vaccination
coverage survey, Greece, 2006
n 95 CI
Place of residence Urban Rural 1,676 448 65 58 63-67 52-61
Maternal attitude Positive Negative 1,993 24 65 52 62-71 49-62
Weighted allowing for clustering 95
Confidence Interval
32
Table 2. Clinical characteristics of 102 cases of
campylobacteriosis, Ireland, 2002
Text must be alighned to the left
Characteristics Value
Total cases 102
Median age (years) Range (years) Fever Diarrhoea Joint pain 35 5-83 65 (65.6 ) 102 (100 ) 4 (4.3)
Headache Muscle pain Isolation of organism 12 (12.4) 4(4.4) Stool samples (5/93)
The table presents frequency of
symmptoms Quantitave variables/other info should
not be here
Sort rows. Decreasing order
33
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
34
Arranging common types of tables in epidemiology
  • Line listing
  • Two variable table
  • Complex table
  • Cohort study
  • Case-control study

Common tables
35
Reported cases of intussusception among
recipients of rotavirus vaccine, by state, United
States, 1998-1999
a. Line listing
State Age1 Sex Days2 Dose
New York 02 M 03 1
California 03 M 03 1
Pennsylvania 06 M 03 1
Pennsylvania 02 M 04 1
Colorado 04 F 04 1
California 07 M 04 2
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
Pennsylvania 02 M 29 1
California 05 M 59 1
MMWR, 48 (27)577  
1. Age in months
2. Days from dose to symptom onset
Common tables
36
New cases of primary and secondary syphilis by
age group and sex, United States, 1989
b. Two variable table
Age group Cases (100s) Cases (100s) Cases (100s)
(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
Common tables
37
Complex table
c. Complex table
Children Children Children Children
Character Character Character Exp (n205) Exp (n205) Not exp (n8729) p
Gestational age (weeks) at birth Gestational age (weeks) at birth Gestational age (weeks) at birth Gestational age (weeks) at birth Gestational age (weeks) at birth
lt25 lt25 5.8 14 0.04
25-29 25-29 18.0 19 NS
Birthweight (kg) Birthweight (kg) Birthweight (kg) Birthweight (kg)
1.5 1.5 15 .0 15 NS
2.5 2.5 39 .0 43 NS
Common tables
38
2x2 table for calculation of measure of effect
d. Cohort study
ill
not ill
49 49 98
ate ham
did not ham
4 6 10
39
Tab. IV Fish consumption and gastro-intestinal
illness among customers at Uncle Mikes Fish
Chips, Berlin, 2005
d. Cohort study
Ill Total Attack rate Relative risk
Ate fish 42 58 72 9.3 (3.9-22)
Did not eat fish 5 64 8 Ref
Total 47 122 39
2x2 table for caclulations Not for presentation
40
Risk of ______ by exposure, among residents
of Place, time
d. Cohort study
Exposed Exposed Exposed
Exposure Res. a Yes Yes No RRc (95 CId)
Exposure Res. a n ARb n ARb RRc (95 CId)
Type 1
Sub Type 1-A ( - )
Sub Type 1-B ( - )
Sub Type 1-C ( - )
Type 2 ( - )
Type 3 ( - )
Type 4
a. Res. Responded
b. AR Attack Rate cases per ___
c. RR Risk Ratio
d. 95 CI 95 confidence interval of the RR
Common tables
41
Risk of ______ by exposure, among residents
of Place, time
d. Cohort study (reference group)
Exposed 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
a. AR Attack Rate cases per ___
b. RR Risk Ratio
c. 95 CI 95 confidence interval of the RR
Common tables
42
Case control study
Cases
Controls Odds ratio
50 20 4
a b
Exposed
Not exposed
50 80 c d
100
Total
100
43
Exposures () among cases and controls,
Place, Time
e. Case control study
Exposed (n) a 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) ( )
a. n subjects responding
b. OR Odds Ratio
Common tables
c. 95 CI 95 confidence interval of the OR
44
Table from a case control study
45
Food Specific Attack Rates, Outbreak of
Salmonellosis, Prison X, Dover, Delaware,
September 1992
46
REVISED for oral presentation Food specific
attack rates, outbreak of Salmonellosis, prison
X, Dover, Delaware, September 1992
47
Take home message
  • Design your table around the message that is
    contained in your data

48
Practical 1
  • Spot the errors of the following tables

49
SmiNet database 2005-2011
2.3. Reported laboratory diagnosis methods for chronic and acute infections 2.3. Reported laboratory diagnosis methods for chronic and acute infections 2.3. Reported laboratory diagnosis methods for chronic and acute infections 2.3. Reported laboratory diagnosis methods for chronic and acute infections 2.3. Reported laboratory diagnosis methods for chronic and acute infections
Lab. method anti-HCV anti-HCV RNA-HCV RNA-HCV Data missing
Chronic cases (n10403) 4084 (40.3) 2659 (25.4) 2057 (20) 1603 (15)
Acute cases (n956) 383 (40.4) 260 (27.3) 199 (21.2) 114 (12.4)
Seroconversion could not be verified for the VHC
acute cases.
  • Place acute and chronic vertically to facilitate
    comparison
  • Round up proportions
  • Add thousand dividers

50
Reported laboratory diagnosis methods for
chronic and acute HCV infections, SmiNet database
2005-2011
Information available among cases Acute cases Acute cases Chronic cases Chronic cases
Information available among 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
Seroconversion could not be verified for acute
hepatitis C cases.
- Vertical comparisons - Rounded proportions -
Thousand dividers
51
CMOs reporting procedures
  • 19/21 CMOs replied the questionnaire

Easy to apply case definitions? Yes (Both chronic and acute) Yes (Only chronic) Yes (Only acute) No
Replies (n19) 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 (n19) 12 (63) 2 (10) 1 (5) 4 (21)
  • Two tables with identical structure
  • Incomplete title

52
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
Case definition easily applicable For chronic cases only 1 5
Case definition easily applicable For acute cases only 0 0
Case definition easily applicable No 9 47
Reporting instruction for laboratory After confirmation (Iblot) 12 63
Reporting instruction for laboratory After any antibody test 2 10
Reporting instruction for laboratory Wait for RNA 1 5
Reporting instruction for laboratory Other 4 21
Total Total 19 100
  • Merged table
  • Time, place and person title

53
Sexually transmitted infections (STIs)
  • Two parts in table Values and changes
  • Footnote too small / detailed
  • Heterogeneous content indicator-wise
  • 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 Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England Number of new STI diagnoses in 2009-11, and changes in trend in 2002-11, England
New STI diagnoses Year Year Year Change Change Change
New STI diagnoses 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/HP
AwebFile/HPAweb_C/1215589015024
53
54
Practical 2
  • Prepare dummy tables for a
  • case-control study
  • cross-sectional study

55
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

56
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

57
Exposures () among cases of campylobacter
and controls, Place, Time
Exposed (n) a Exposed (n) a
Exposure Cases Controls OR b 95 CI c
Agegtmedian Food (n) (n) ( )
Chicken (n) (n) ( )
Lettuce (n) (n) ( )
Travel abroad (n) (n) ( )
Domestic animal (n) (n) ( )
a. n subjects responding
b. OR Odds Ratio
c. 95 CI 95 confidence interval of the OR
58
Prevalence of West Nile virus infection by
exposure, among residents of Place, time
Exposed Exposed
Exposure P a PR b 95 CI c
Population size Urban Rural
Population size Urban Rural 1.0 Referent
Mosquito protection
Often Rarely Never 1.0 Referent
a. P Prevalence cases per ___
b. RR Prevalence Ratio
c. 95 CI 95 confidence interval of the RR
Common tables
59
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

60
BACK-UP SLIDES
61
Results
Information hard to follow as table
  • Number of cases submitted to USISS

Age group Type lt1 1 to 4 5 to 14 15 to 44 45 to 64 65 Total
A(H1N1) 2 4 1 6 5 7 25
A(H3N2) 5 8 3 16 18 17 67
A(unknown) 10 20 8 34 21 40 133
B 2 0 4 2 8 3 19
Total 19 32 16 58 52 67 244
62
Number of cases submitted to USISS, by age and
virus, Place, Time
Data presented at as graph
63
Results
Exposed Exposed Exposed Unexposed Unexposed Unexposed
Exposure Total Cases AR Total Cases AR RR Confidence interval P
blood glucose monitoring 30 8 26.67 56 0 0.00 20.26 3.18-8 lt0.001
diabetes mellitus 40 8 20 46 0 0.00 11.05 1.71-8 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 1.01-8. 0.048
upper floor 57 8 14,04 29 0 0.00 5.62 0.87-8 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
- Redundant stats - Alignment - Decimals -
Neutral title
Multivariable analysis only blood glucose
monitoring significant
64
Risk of hepatitis B according to selected
exposures, nursing home, Saxony, Germany, 2011
Exposed Exposed Exposed Unexposed Unexposed Unexposed
Exposure Total Cases AR Total Cases AR Relative risk Confidence interval
Glucose monitoring 30 8 27 56 0 0 20 3.2-8
Diabetes mellitus 40 8 20 46 0 0 11 1.7-8
Insulin injection 25 6 24 61 2 3 7.3 1.6-34
Chiropody 53 8 15 33 0 0 6.4 1.0-8.
Upper floor 57 8 14 29 0 0 5.6 0.87-8
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 .-.
- Full title - Rounding off - Alignment - P
values deleted
Multivariable analysis Only blood glucose
monitoring significant
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