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Coerce Data to SaTScan Population Table

Source: R/ss_tbl.R
ss_pop.Rd

Creates an ss_tbl object of type "pop" (SaTScan Population File). A population file provides the population-at-risk by location and time and is used as the denominator for Poisson-based scan statistics. If multiple time points are supplied, SaTScan may interpolate population size between time anchors depending on the analysis setup.

This constructor records the mappings for location ID, time, population, and optional covariate strata without changing the input data. Any time formatting is deferred to write_satscan(), using time_precision if provided.

Usage

ss_pop(data, loc_id, time, population, covars = NULL, time_precision = NULL)

Arguments

data

A data frame containing population data.

loc_id

Column name for location ID.

time

Column name for time (census year/time).

population

Column name for population count.

covars

Optional vector of column names for covariates.

time_precision

User-specified time precision (e.g. "year" to format Dates as YYYY).

Value

An ss_tbl object of type "pop".

SaTScan File Specification

The Population File has the following structure: <LocationID> <Year/Time> <Population> <Covariate1> ...

  • LocationID: Character or numeric identifier. Match cases and geo.

  • Year/Time: The "census year" or time point. For daily analysis, you can still use yearly population anchors (e.g. 2023, 2024). SaTScan interpolates linearly.

  • Population: The count of people at risk.

  • Covariates: Optional. If used, population must be stratified by these covariates.