Summary of the Results of a Case-crossover Model

The default summary method for an object produced by casecross(). Shows the number of control days, the average number of control days per case days, and the parameter estimates.

Usage

# S3 method for class 'casecross'
summary(object, ...)

Arguments

object

a casecross() object produced by casecross().

...

further arguments passed to or from other methods.

Value

The number of control days, the average number of control days per case days, and the parameter estimates.

See also

casecross()

Author

Adrian Barnett a.barnett@qut.edu.au

Examples

# \donttest{
# cardiovascular disease data
# subset for example
CVDdaily <- subset(CVDdaily, date <= as.Date('1987-12-31'))
# Effect of ozone on CVD death
model1 <- casecross(
  cvd ~ o3mean + tmpd + Mon + Tue + Wed + Thu + Fri + Sat,
  data = CVDdaily
)
summary(model1)
#> Time-stratified case-crossover with a stratum length of 28 days
#> Total number of cases 17502 
#> Number of case days with available control days 364 
#> Average number of control days per case day 23.2 
#> 
#> Parameter Estimates:
#>                coef exp(coef)    se(coef)           z   Pr(>|z|)
#> o3mean -0.002882613 0.9971215 0.001128975 -2.55330077 0.01067073
#> tmpd    0.001461400 1.0014625 0.001981047  0.73769030 0.46070267
#> Mon     0.042733425 1.0436596 0.028942815  1.47647783 0.13981566
#> Tue     0.057910712 1.0596204 0.028772745  2.01269332 0.04414690
#> Wed    -0.010008025 0.9900419 0.029171937 -0.34307029 0.73154558
#> Thu    -0.016790296 0.9833499 0.029455877 -0.57001513 0.56866744
#> Fri     0.027247952 1.0276226 0.029173235  0.93400517 0.35030123
#> Sat     0.001855841 1.0018576 0.028900116  0.06421568 0.94879849
# match on day of the week
model2 <- casecross(cvd ~ o3mean + tmpd, matchdow = TRUE, data = CVDdaily)
summary(model2)
#> Time-stratified case-crossover with a stratum length of 28 days
#> Matched on day of the week
#> Total number of cases 17502 
#> Number of case days with available control days 364 
#> Average number of control days per case day 3 
#> 
#> Parameter Estimates:
#>                 coef exp(coef)    se(coef)          z    Pr(>|z|)
#> o3mean -0.0030752572 0.9969295 0.001188540 -2.5874238 0.009669658
#> tmpd   -0.0004095116 0.9995906 0.002131744 -0.1921017 0.847662557
# match on temperature to within a degree
model3 <- casecross(
  cvd ~ o3mean + Mon + Tue + Wed + Thu + Fri + Sat,
  data = CVDdaily,
  matchconf = 'tmpd',
  confrange = 1
)
summary(model3)
#> Time-stratified case-crossover with a stratum length of 28 days
#> Matched on tmpd plus/minus 1 
#> Total number of cases 15180 
#> Number of case days with available control days 318 
#> Average number of control days per case day 4.9 
#> 
#> Parameter Estimates:
#>                coef exp(coef)   se(coef)          z     Pr(>|z|)
#> o3mean -0.003238583 0.9967667 0.00131839 -2.4564691 1.403099e-02
#> Mon     0.182058170 1.1996840 0.03577818  5.0885255 3.608582e-07
#> Tue     0.144181049 1.1550932 0.03563272  4.0463108 5.203115e-05
#> Wed     0.099443480 1.1045560 0.03554924  2.7973451 5.152447e-03
#> Thu     0.088518237 1.0925542 0.03459482  2.5587140 1.050601e-02
#> Fri     0.108107305 1.1141673 0.03437323  3.1451022 1.660288e-03
#> Sat     0.023660066 1.0239422 0.03525152  0.6711786 5.021068e-01
# }