movStats | R Documentation |

Moving Estimates Using Overlapping Windows

```
movStats(
formula,
stat = NULL,
discrete = FALSE,
space = c("n", "x"),
eps = if (space == "n") 15,
varyeps = FALSE,
nignore = 10,
xinc = NULL,
xlim = NULL,
times = NULL,
tunits = "year",
msmooth = c("smoothed", "raw", "both"),
tsmooth = c("supsmu", "lowess"),
bass = 8,
span = 1/4,
maxdim = 6,
penalty = NULL,
trans = function(x) x,
itrans = function(x) x,
loess = FALSE,
ols = FALSE,
qreg = FALSE,
lrm = FALSE,
orm = FALSE,
hare = FALSE,
lrm_args = NULL,
family = "logistic",
k = 5,
tau = (1:3)/4,
melt = FALSE,
data = environment(formula),
pr = c("none", "kable", "plain", "margin")
)
```

`formula` |
a formula with the analysis variable on the left and the x-variable on the right, following by optional stratification variables |

`stat` |
function of one argument that returns a named list of computed values. Defaults to computing mean and quartiles + N except when y is binary in which case it computes moving proportions. If y has two columns the default statistics are Kaplan-Meier estimates of cumulative incidence at a vector of |

`discrete` |
set to |

`space` |
defines whether intervals used fixed width or fixed sample size |

`eps` |
tolerance for window (half width of window). For |

`varyeps` |
applies to |

`nignore` |
see description, default is to exclude |

`xinc` |
increment in x to evaluate stats, default is xlim range/100 for |

`xlim` |
2-vector of limits to evaluate if |

`times` |
vector of times for evaluating one minus Kaplan-Meier estimates |

`tunits` |
time units when |

`msmooth` |
set to |

`tsmooth` |
defaults to the super-smoother |

`bass` |
the |

`span` |
the |

`maxdim` |
passed to |

`penalty` |
passed to |

`trans` |
transformation to apply to x |

`itrans` |
inverse transformation |

`loess` |
set to TRUE to also compute loess estimates |

`ols` |
set to TRUE to include rcspline estimate of mean using ols |

`qreg` |
set to TRUE to include quantile regression estimates w rcspline |

`lrm` |
set to TRUE to include logistic regression estimates w rcspline |

`orm` |
set to TRUE to include ordinal logistic regression estimates w rcspline (mean + quantiles in |

`hare` |
set to TRUE to include hazard regression estimtes of incidence at |

`lrm_args` |
a |

`family` |
link function for ordinal regression (see |

`k` |
number of knots to use for ols and/or qreg rcspline |

`tau` |
quantile numbers to estimate with quantile regression |

`melt` |
set to TRUE to melt data table and derive Type and Statistic |

`data` |
data.table or data.frame, default is calling frame |

`pr` |
defaults to no printing of window information. Use |

Function to compute moving averages and other statistics as a function
of a continuous variable, possibly stratified by other variables.
Estimates are made by creating overlapping moving windows and
computing the statistics defined in the stat function for each window.
The default method, `space='n'`

creates varying-width intervals each having a sample size of `2*eps +1`

, and the smooth estimates are made every `xinc`

observations. Outer intervals are not symmetric in sample size (but the mean x in those intervals will reflect that) unless `eps=nignore`

, as outer intervals are centered at observations `nignore`

and `n - nignore + 1`

where the default for `nignore`

is 10. The mean x-variable within each windows is taken to represent that window. If `trans`

and `itrans`

are given, x means are computed on the `trans(x)`

scale and then `itrans`

'd. For `space='x'`

, by default estimates are made on to the `nignore`

smallest to the `nignore`

largest
observed values of the x variable to avoid extrapolation and to
help getting the moving statistics off on an adequate start for
the left tail. Also by default the moving estimates are smoothed using `supsmu`

.
When `melt=TRUE`

you can feed the result into `ggplot`

like this:
`ggplot(w, aes(x=age, y=crea, col=Type)) + geom_line() +`

`facet_wrap(~ Statistic)`

See here for several examples.

a data table, with attribute `infon`

which is a data frame with rows corresponding to strata and columns `N`

, `Wmean`

, `Wmin`

, `Wmax`

if `stat`

computed `N`

. These summarize the number of observations used in the windows. If `varyeps=TRUE`

there is an additional column `eps`

with the computed per-stratum `eps`

. When `space='n'`

and `xinc`

is not given, the computed `xinc`

also appears as a column. An additional attribute `info`

is a `kable`

object ready for printing to describe the window characteristics.

Frank Harrell

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