binary_exposure {eesim}

Simulate binary exposure data

Description

Simulates a time series of binary exposure values with or without seasonal trends.

Usage

binary_exposure(n, p, trend = "no trend", slope, amp = 0.05,
  start.date = "2000-01-01", cust_expdraw = NULL,
  cust_expdraw_args = list(), custom_func = NULL, ...)

Arguments

n

A non-negative integer specifying the number of days to simulate.

p

A numeric value between 0 and 1 giving the mean probability of exposure across study days.

trend

A character string that gives the trend function to use. Options are:

• "no trend": No trend, either seasonal or long-term (default).

• "cos1": A seasonal trend only.

• "cos2": A seasonal trend with variable amplitude across years.

• "cos3": A seasonal trend with steadily decreasing amplitude over time.

• "linear": A linear long-term trend with no seasonal trend.

• "monthly": Uses a user-specified probability of exposure for each month.

slope

A numeric value specifying the slope of the trend, to be used with trend = "linear" or trend = "cos1linear".

amp

A numeric value specifying the amplitude of the seasonal trend. Must be between -.5 and .5.

start.date

A date of the format "yyyy-mm-dd" from which to begin simulating daily exposures

cust_expdraw

An R object name specifying a user-created function which determines the distribution of random noise off of the trend line. This function must have inputs "n" and "prob" and output a vector of simulated exposure values.

cust_expdraw_args

A list of arguments other than n required by the cust_expdraw function.

custom_func

An R object specifying a customized function from which to create a trend variable. Must accept arguments n and p.

...

Optional arguments to a custom trend function

Value

A data frame with columns for the dates and daily exposure values for n days.

Examples

binary_exposure(n = 5, p = 0.1, trend = "cos1", amp = .02,
                start.date = "2001-02-01")
binary_exposure(n=10, p=.1, cust_expdraw=rnbinom,
                cust_expdraw_args=list(size=10))