1 Cross tables
Two-way tables are used extensively in healthcare research, e.g. a 2x2 table comparing two factors with two levels each, or table 1 from a typical clinical study or trial
The main functions all take a dependent
variable - the outcome (maximum of 5 levels) - and explanatory
variables - predictors or exposures (any number categorical or continuous variables).
1.01 Default
Age (years) |
Mean (SD) |
59.8 (11.9) |
58.4 (13.3) |
Age |
<40 years |
68 (97.1) |
2 (2.9) |
|
40-59 years |
334 (97.1) |
10 (2.9) |
|
60+ years |
500 (97.1) |
15 (2.9) |
Sex |
Female |
432 (97.1) |
13 (2.9) |
|
Male |
470 (97.1) |
14 (2.9) |
Obstruction |
No |
715 (97.7) |
17 (2.3) |
|
Yes |
166 (94.3) |
10 (5.7) |
Note, chi-squared warnings will be generated when the expected count in any cell is less than 5. Fisher’s exact test has not been implemented, given it is so easy to go straight to a univariable logistic regression, e.g. colon_s %>% finalfit(dependent, explanatory)
1.02 Add or edit variable labels
Age (years) |
Mean (SD) |
59.8 (11.9) |
58.4 (13.3) |
Age |
<40 years |
68 (97.1) |
2 (2.9) |
|
40-59 years |
334 (97.1) |
10 (2.9) |
|
60+ years |
500 (97.1) |
15 (2.9) |
Gender |
Female |
432 (97.1) |
13 (2.9) |
|
Male |
470 (97.1) |
14 (2.9) |
Obstruction |
No |
715 (97.7) |
17 (2.3) |
|
Yes |
166 (94.3) |
10 (5.7) |
1.03 P-value for hypothesis test
Chi-squared for categorical, Kruskal-Wallis/Mann-Whitney for continuous
Age (years) |
Mean (SD) |
59.8 (11.9) |
58.4 (13.3) |
0.578 |
Age |
<40 years |
68 (97.1) |
2 (2.9) |
1.000 |
|
40-59 years |
334 (97.1) |
10 (2.9) |
|
|
60+ years |
500 (97.1) |
15 (2.9) |
|
Sex |
Female |
432 (97.1) |
13 (2.9) |
0.979 |
|
Male |
470 (97.1) |
14 (2.9) |
|
Obstruction |
No |
715 (97.7) |
17 (2.3) |
0.018 |
|
Yes |
166 (94.3) |
10 (5.7) |
|
1.05 Missing values for the explanatory variables
Always do this when describing your data.
Age (years) |
Median (IQR) |
61.0 (16.0) |
60.0 (18.0) |
0.578 |
Age |
<40 years |
68 (97.1) |
2 (2.9) |
1.000 |
|
40-59 years |
334 (97.1) |
10 (2.9) |
|
|
60+ years |
500 (97.1) |
15 (2.9) |
|
Sex |
Female |
432 (97.1) |
13 (2.9) |
0.979 |
|
Male |
470 (97.1) |
14 (2.9) |
|
Obstruction |
No |
715 (97.7) |
17 (2.3) |
0.042 |
|
Yes |
166 (94.3) |
10 (5.7) |
|
|
Missing |
21 (100.0) |
0 (0.0) |
|
1.06 Column proportions (rather than row)
Age (years) |
Median (IQR) |
61.0 (16.0) |
60.0 (18.0) |
0.578 |
Age |
<40 years |
68 (7.5) |
2 (7.4) |
1.000 |
|
40-59 years |
334 (37.0) |
10 (37.0) |
|
|
60+ years |
500 (55.4) |
15 (55.6) |
|
Sex |
Female |
432 (47.9) |
13 (48.1) |
0.979 |
|
Male |
470 (52.1) |
14 (51.9) |
|
Obstruction |
No |
715 (79.3) |
17 (63.0) |
0.042 |
|
Yes |
166 (18.4) |
10 (37.0) |
|
|
Missing |
21 (2.3) |
0 (0.0) |
|
1.07 Total column
Age (years) |
Median (IQR) |
61.0 (16.0) |
60.0 (18.0) |
NA |
0.578 |
Age |
<40 years |
68 (7.5) |
2 (7.4) |
70 (7.5) |
1.000 |
|
40-59 years |
334 (37.0) |
10 (37.0) |
344 (37.0) |
|
|
60+ years |
500 (55.4) |
15 (55.6) |
515 (55.4) |
|
Sex |
Female |
432 (47.9) |
13 (48.1) |
445 (47.9) |
0.979 |
|
Male |
470 (52.1) |
14 (51.9) |
484 (52.1) |
|
Obstruction |
No |
715 (79.3) |
17 (63.0) |
732 (78.8) |
0.042 |
|
Yes |
166 (18.4) |
10 (37.0) |
176 (18.9) |
|
|
Missing |
21 (2.3) |
0 (0.0) |
21 (2.3) |
|
1.08 Order a variable by total
This is intended for when there is only one explanatory
variable.
Extent of spread |
Serosa |
736 (81.6) |
23 (85.2) |
759 (81.7) |
0.200 |
|
Muscle |
105 (11.6) |
1 (3.7) |
106 (11.4) |
|
|
Adjacent structures |
40 (4.4) |
3 (11.1) |
43 (4.6) |
|
|
Submucosa |
21 (2.3) |
0 (0.0) |
21 (2.3) |
|
1.09 Label with dependent
name
Age (years) |
Median (IQR) |
61.0 (16.0) |
60.0 (18.0) |
NA |
0.578 |
Age |
<40 years |
68 (7.5) |
2 (7.4) |
70 (7.5) |
1.000 |
|
40-59 years |
334 (37.0) |
10 (37.0) |
344 (37.0) |
|
|
60+ years |
500 (55.4) |
15 (55.6) |
515 (55.4) |
|
Sex |
Female |
432 (47.9) |
13 (48.1) |
445 (47.9) |
0.979 |
|
Male |
470 (52.1) |
14 (51.9) |
484 (52.1) |
|
Obstruction |
No |
715 (79.3) |
17 (63.0) |
732 (78.8) |
0.042 |
|
Yes |
166 (18.4) |
10 (37.0) |
176 (18.9) |
|
|
Missing |
21 (2.3) |
0 (0.0) |
21 (2.3) |
|
The dependent name cannot be passed directly to the table intentionally. This is to avoid errors when code is copied and the name is not updated. Change the dependent label using the following. The prefix (“Dependent:”) and any suffix can be altered.
Age (years) |
Median (IQR) |
61.0 (16.0) |
60.0 (18.0) |
NA |
0.578 |
Age |
<40 years |
68 (7.5) |
2 (7.4) |
70 (7.5) |
1.000 |
|
40-59 years |
334 (37.0) |
10 (37.0) |
344 (37.0) |
|
|
60+ years |
500 (55.4) |
15 (55.6) |
515 (55.4) |
|
Sex |
Female |
432 (47.9) |
13 (48.1) |
445 (47.9) |
0.979 |
|
Male |
470 (52.1) |
14 (51.9) |
484 (52.1) |
|
Obstruction |
No |
715 (79.3) |
17 (63.0) |
732 (78.8) |
0.042 |
|
Yes |
166 (18.4) |
10 (37.0) |
176 (18.9) |
|
|
Missing |
21 (2.3) |
0 (0.0) |
21 (2.3) |
|
1.10 Dependent variable with 0 to 5 factor levels supported
Age (years) |
Median (IQR) |
61.0 (12.5) |
61.5 (14.0) |
61.0 (16.0) |
56.0 (14.0) |
NA |
0.334 |
Age |
<40 years |
4 (9.3) |
8 (7.5) |
56 (7.4) |
2 (9.5) |
70 (7.5) |
0.338 |
|
40-59 years |
15 (34.9) |
32 (30.2) |
285 (37.5) |
12 (57.1) |
344 (37.0) |
|
|
60+ years |
24 (55.8) |
66 (62.3) |
418 (55.1) |
7 (33.3) |
515 (55.4) |
|
Sex |
Female |
19 (44.2) |
47 (44.3) |
366 (48.2) |
13 (61.9) |
445 (47.9) |
0.483 |
|
Male |
24 (55.8) |
59 (55.7) |
393 (51.8) |
8 (38.1) |
484 (52.1) |
|
Obstruction |
No |
36 (83.7) |
88 (83.0) |
588 (77.5) |
20 (95.2) |
732 (78.8) |
0.037 |
|
Yes |
5 (11.6) |
13 (12.3) |
157 (20.7) |
1 (4.8) |
176 (18.9) |
|
|
Missing |
2 (4.7) |
5 (4.7) |
14 (1.8) |
0 (0.0) |
21 (2.3) |
|
1.11 Explanatory variable defaults to factor when ≤5 distinct values
extent |
1 |
16 (80.0) |
4 (20.0) |
|
2 |
78 (75.7) |
25 (24.3) |
|
3 |
401 (53.5) |
349 (46.5) |
|
4 |
16 (38.1) |
26 (61.9) |
1.12 Keep as continous variable when ≤5 distinct values
extent |
Mean (SD) |
2.8 (0.5) |
3.0 (0.4) |
2.01 Default
Logistic regression first.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.12 (0.51-2.44, p=0.770) |
2.02 Hide reference levels
Most appropriate when all explanatory variables are continuous or well-known binary variables, such as sex.
Age (years) |
Mean (SD) |
59.8 (11.4) |
59.9 (12.5) |
1.00 (0.99-1.01, p=0.986) |
1.00 (0.99-1.01, p=0.983) |
Sex |
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.76-1.27, p=0.888) |
2.03 Model metrics
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.12 (0.51-2.44, p=0.770) |
Number in dataframe = 929, Number in model = 894, Missing = 35, AIC = 1230.7, C-statistic = 0.56, H&L = Chi-sq(8) 5.69 (p=0.682) |
2.04 Model metrics can be applied to all supported base models
Number in dataframe = 929, Number in model = 894, Missing = 35, AIC = 1230.7, C-statistic = 0.56, H&L = Chi-sq(8) 5.69 (p=0.682) |
2.05 Reduced model
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.424) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
- |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.26 (0.90-1.76, p=0.176) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
- |
2.06 Include all models
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
0.81 (0.48-1.36, p=0.424) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
- |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
1.26 (0.90-1.76, p=0.176) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.12 (0.51-2.44, p=0.770) |
- |
Number in dataframe = 929, Number in model = 894, Missing = 35, AIC = 1230.7, C-statistic = 0.56, H&L = Chi-sq(8) 5.69 (p=0.682) |
Number in dataframe = 929, Number in model = 894, Missing = 35, AIC = 1226.8, C-statistic = 0.555, H&L = Chi-sq(8) 0.06 (p=1.000) |
2.06 Interactions
Interactions can be specified in the normal way. Formatting the output is trickier. At the moment, we have left the default model output. This can be adjusted as necessary.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.65 (0.32-1.34, p=0.241) |
0.66 (0.32-1.36, p=0.258) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.80 (0.40-1.61, p=0.529) |
0.85 (0.42-1.71, p=0.647) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
1.24 (0.47-3.30, p=0.665) |
1.17 (0.44-3.15, p=0.752) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.26 (0.90-1.76, p=0.182) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.11 (0.50-2.41, p=0.795) |
age.factor40-59 years:sex.factorMale |
Interaction |
- |
- |
0.68 (0.23-1.97, p=0.479) |
0.74 (0.25-2.18, p=0.588) |
age.factor60+ years:sex.factorMale |
Interaction |
- |
- |
0.86 (0.30-2.39, p=0.766) |
0.89 (0.31-2.51, p=0.822) |
2.07 Interactions: create interaction variable with two factors
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.26 (0.90-1.76, p=0.182) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.11 (0.50-2.41, p=0.795) |
Age:Sex |
<40 years|Female |
18 (3.5) |
19 (4.7) |
- |
- |
|
<40 years|Male |
13 (2.5) |
17 (4.2) |
1.24 (0.47-3.30, p=0.665) |
1.17 (0.44-3.15, p=0.752) |
|
40-59 years|Female |
96 (18.8) |
66 (16.3) |
0.65 (0.32-1.34, p=0.241) |
0.66 (0.32-1.36, p=0.258) |
|
40-59 years|Male |
112 (21.9) |
65 (16.1) |
0.55 (0.27-1.12, p=0.100) |
0.57 (0.28-1.18, p=0.129) |
|
60+ years|Female |
129 (25.2) |
109 (27.0) |
0.80 (0.40-1.61, p=0.529) |
0.85 (0.42-1.71, p=0.647) |
|
60+ years|Male |
143 (28.0) |
128 (31.7) |
0.85 (0.42-1.69, p=0.638) |
0.88 (0.44-1.77, p=0.725) |
2.08 Dependent name
The dependent name cannot be specified directly intentionally. This is to prevent errors when copying code. Re-label using ff_label()
. The dependent prefix and suffix can also be altered.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.12 (0.51-2.44, p=0.770) |
2.09 Estimate name
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.12 (0.51-2.44, p=0.770) |
2.10 Digits / decimal places
Number of digits to round to regression results. (1) estimate, (2) confidence interval limits, (3) p-value. Default is c(2,2,3). Trailing zeros are preserved. Number of decimal places for counts and mean (sd) / median (IQR) not currently supported. Defaults are senisble :)
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.542 (0.319-0.918, p=0.0230) |
0.574 (0.335-0.978, p=0.0412) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.750 (0.448-1.250, p=0.2704) |
0.810 (0.481-1.360, p=0.4261) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.981 (0.756-1.275, p=0.8886) |
0.983 (0.754-1.283, p=0.9023) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.249 (0.896-1.741, p=0.1892) |
1.255 (0.896-1.757, p=0.1859) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.180 (0.542-2.553, p=0.6716) |
1.122 (0.512-2.442, p=0.7699) |
2.11 Confidence interval type
One of c("profile", "default")
for GLM models (confint.glm()
). Note, a little awkwardly, the ‘default’ setting is profile
, rather than default
. Profile levels are probably a little more accurate. Only go to default if taking a significant length of time for profile, i.e. data is greater than hundreds of thousands of lines.
For glmer/lmer models (confint.merMod()
), c("profile", "Wald", "boot")
. Not implemented for lm()
, coxph()
or coxphlist
, which use default.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.55-2.54, p=0.672) |
1.12 (0.52-2.43, p=0.770) |
2.12 Confidence interval level
Probably never change this :) Note, the p-value is intentionally not included for confidence levels other than 95% to avoid confusion.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.35-0.84) |
0.57 (0.37-0.90) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.49-1.15) |
0.81 (0.52-1.25) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.79-1.22) |
0.98 (0.79-1.23) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.95-1.65) |
1.25 (0.95-1.66) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.62-2.25) |
1.12 (0.58-2.15) |
2.13 Confidence interval separation
Some like to avoid the hyphen so as not to confuse with minus sign. Obviously not an issue in logistic regression.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32 to 0.92, p=0.023) |
0.57 (0.34 to 0.98, p=0.041) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45 to 1.25, p=0.270) |
0.81 (0.48 to 1.36, p=0.426) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76 to 1.27, p=0.889) |
0.98 (0.75 to 1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90 to 1.74, p=0.189) |
1.25 (0.90 to 1.76, p=0.186) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54 to 2.55, p=0.672) |
1.12 (0.51 to 2.44, p=0.770) |
2.14 Mixed effects random-intercept model
At its simplest, a random-intercept model can be specified using a single quoted variable. In this example, it is the equivalent of quoting random_effect = "(1 | hospital)"
.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.75 (0.39-1.44, p=0.382) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
1.03 (0.55-1.96, p=0.916) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.80 (0.58-1.11, p=0.180) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.23 (0.82-1.83, p=0.320) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.03 (0.43-2.51, p=0.940) |
2.15 Mixed effects random-slope model
In the example below, allow the effect of age on outcome to vary by hospital. Note, this specification must have parentheses included.
Age |
<40 years |
31 (6.1) |
36 (8.9) |
- |
- |
|
40-59 years |
208 (40.7) |
131 (32.4) |
0.54 (0.32-0.92, p=0.023) |
0.81 (0.37-1.81, p=0.611) |
|
60+ years |
272 (53.2) |
237 (58.7) |
0.75 (0.45-1.25, p=0.270) |
1.08 (0.54-2.20, p=0.822) |
Sex |
Female |
243 (47.6) |
194 (48.0) |
- |
- |
|
Male |
268 (52.4) |
210 (52.0) |
0.98 (0.76-1.27, p=0.889) |
0.80 (0.58-1.11, p=0.179) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.24 (0.83-1.85, p=0.298) |
Perforation |
No |
497 (97.3) |
391 (96.8) |
- |
- |
|
Yes |
14 (2.7) |
13 (3.2) |
1.18 (0.54-2.55, p=0.672) |
1.02 (0.42-2.48, p=0.967) |
2.16 Mixed effects random-slope model directly from lme4
Clearly, as models get more complex, parameters such as random effect group variances may require to be extracted directly from model outputs.
(Intercept) |
-0.2537662 |
0.8983060 |
-0.2824941 |
0.7775646 |
fixed |
age.factor40-59 years |
-0.3285638 |
0.3830047 |
-0.8578582 |
0.3909707 |
fixed |
age.factor60+ years |
-0.0531730 |
0.3450263 |
-0.1541128 |
0.8775208 |
fixed |
sd_(Intercept).hospital |
1.8670680 |
NA |
NA |
NA |
hospital |
sd_age.factor40-59 years.hospital |
0.3382630 |
NA |
NA |
NA |
hospital |
sd_age.factor60+ years.hospital |
0.0826644 |
NA |
NA |
NA |
hospital |
cor_(Intercept).age.factor40-59 years.hospital |
-0.9999999 |
NA |
NA |
NA |
hospital |
cor_(Intercept).age.factor60+ years.hospital |
-0.9999997 |
NA |
NA |
NA |
hospital |
cor_age.factor40-59 years.age.factor60+ years.hospital |
0.9999998 |
NA |
NA |
NA |
hospital |
2.17 Exclude all missing data in final model from univariable analyses
This can be useful if you want the numbers in the final table to match the final multivariable model. However, be careful to include a full explanation of this in the methods and the reason for exluding the missing data.
Age |
<40 years |
31 (6.2) |
35 (8.8) |
- |
- |
|
40-59 years |
203 (40.8) |
129 (32.5) |
0.56 (0.33-0.96, p=0.034) |
0.57 (0.34-0.98, p=0.041) |
|
60+ years |
263 (52.9) |
233 (58.7) |
0.78 (0.47-1.31, p=0.356) |
0.81 (0.48-1.36, p=0.426) |
Sex |
Female |
237 (47.7) |
192 (48.4) |
- |
- |
|
Male |
260 (52.3) |
205 (51.6) |
0.97 (0.75-1.27, p=0.841) |
0.98 (0.75-1.28, p=0.902) |
Obstruction |
No |
408 (82.1) |
312 (78.6) |
- |
- |
|
Yes |
89 (17.9) |
85 (21.4) |
1.25 (0.90-1.74, p=0.189) |
1.25 (0.90-1.76, p=0.186) |
Perforation |
No |
483 (97.2) |
384 (96.7) |
- |
- |
|
Yes |
14 (2.8) |
13 (3.3) |
1.17 (0.54-2.53, p=0.691) |
1.12 (0.51-2.44, p=0.770) |
2.18 Linear regression
Age |
<40 years |
4.7 (4.5) |
- |
- |
|
40-59 years |
3.6 (3.3) |
-1.14 (-2.08 to -0.21, p=0.016) |
-1.21 (-2.16 to -0.26, p=0.012) |
|
60+ years |
3.6 (3.6) |
-1.19 (-2.10 to -0.28, p=0.010) |
-1.25 (-2.18 to -0.33, p=0.008) |
Sex |
Female |
3.7 (3.6) |
- |
- |
|
Male |
3.6 (3.6) |
-0.14 (-0.60 to 0.33, p=0.565) |
-0.07 (-0.54 to 0.40, p=0.779) |
Obstruction |
No |
3.7 (3.7) |
- |
- |
|
Yes |
3.5 (3.2) |
-0.24 (-0.83 to 0.36, p=0.435) |
-0.31 (-0.91 to 0.29, p=0.313) |
Perforation |
No |
3.7 (3.6) |
- |
- |
|
Yes |
3.9 (2.8) |
0.24 (-1.13 to 1.61, p=0.735) |
0.28 (-1.09 to 1.66, p=0.686) |
2.19 Mixed effects random-intercept linear regression
Age |
<40 years |
4.7 (4.5) |
- |
- |
|
40-59 years |
3.6 (3.3) |
-1.14 (-2.08 to -0.21, p=0.016) |
0.45 (0.19 to 1.07, p=0.035) |
|
60+ years |
3.6 (3.6) |
-1.19 (-2.10 to -0.28, p=0.010) |
0.38 (0.16 to 0.87, p=0.011) |
Sex |
Female |
3.7 (3.6) |
- |
- |
|
Male |
3.6 (3.6) |
-0.14 (-0.60 to 0.33, p=0.565) |
0.83 (0.54 to 1.27, p=0.195) |
Obstruction |
No |
3.7 (3.7) |
- |
- |
|
Yes |
3.5 (3.2) |
-0.24 (-0.83 to 0.36, p=0.435) |
0.69 (0.40 to 1.19, p=0.091) |
Perforation |
No |
3.7 (3.6) |
- |
- |
|
Yes |
3.9 (2.8) |
0.24 (-1.13 to 1.61, p=0.735) |
1.26 (0.36 to 4.40, p=0.357) |
2.20 Mixed effects random-slope linear regression
Age |
<40 years |
4.7 (4.5) |
- |
- |
|
40-59 years |
3.6 (3.3) |
-1.14 (-2.08 to -0.21, p=0.016) |
0.47 (0.18 to 1.25, p=0.065) |
|
60+ years |
3.6 (3.6) |
-1.19 (-2.10 to -0.28, p=0.010) |
0.40 (0.17 to 0.92, p=0.016) |
Sex |
Female |
3.7 (3.6) |
- |
- |
|
Male |
3.6 (3.6) |
-0.14 (-0.60 to 0.33, p=0.565) |
0.83 (0.54 to 1.27, p=0.196) |
Obstruction |
No |
3.7 (3.7) |
- |
- |
|
Yes |
3.5 (3.2) |
-0.24 (-0.83 to 0.36, p=0.435) |
0.71 (0.41 to 1.23, p=0.112) |
Perforation |
No |
3.7 (3.6) |
- |
- |
|
Yes |
3.9 (2.8) |
0.24 (-1.13 to 1.61, p=0.735) |
1.22 (0.35 to 4.24, p=0.377) |
2.21 Cox proportional hazards model (survival / time to event)
Age |
<40 years |
- |
- |
|
40-59 years |
0.76 (0.53-1.09, p=0.132) |
0.79 (0.55-1.13, p=0.196) |
|
60+ years |
0.93 (0.66-1.31, p=0.668) |
0.98 (0.69-1.40, p=0.926) |
Sex |
Female |
- |
- |
|
Male |
1.01 (0.84-1.22, p=0.888) |
1.02 (0.85-1.23, p=0.812) |
Obstruction |
No |
- |
- |
|
Yes |
1.29 (1.03-1.62, p=0.028) |
1.30 (1.03-1.64, p=0.026) |
Perforation |
No |
- |
- |
|
Yes |
1.17 (0.70-1.95, p=0.556) |
1.08 (0.64-1.81, p=0.785) |
2.22 Cox proportional hazards model: change dependent label
As above, the dependent label cannot be specfied directly in the model to avoid errors. However, in survival modelling the surivial object specification can be long or awkward. Therefore, here is the work around.
Age |
<40 years |
- |
- |
|
40-59 years |
0.76 (0.53-1.09, p=0.132) |
0.79 (0.55-1.13, p=0.196) |
|
60+ years |
0.93 (0.66-1.31, p=0.668) |
0.98 (0.69-1.40, p=0.926) |
Sex |
Female |
- |
- |
|
Male |
1.01 (0.84-1.22, p=0.888) |
1.02 (0.85-1.23, p=0.812) |
Obstruction |
No |
- |
- |
|
Yes |
1.29 (1.03-1.62, p=0.028) |
1.30 (1.03-1.64, p=0.026) |
Perforation |
No |
- |
- |
|
Yes |
1.17 (0.70-1.95, p=0.556) |
1.08 (0.64-1.81, p=0.785) |