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Returns the computed inclusion probabilities (\(\pi_i = p_{\text{site}} \times p_{\text{period}}\)) for each site-circuit combination in a bus-route creel design. The inclusion probability represents the two-stage sampling probability: the probability that a particular site is visited during a particular sampling period, combining both the site selection probability within the circuit and the circuit (period) selection probability.

Usage

get_inclusion_probs(design)

Arguments

design

A creel_design() object created with survey_type = "bus_route".

Value

A data frame with three columns: the site identifier column, the circuit identifier column, and .pi_i (the computed inclusion probability \(\pi_i = p_{\text{site}} \times p_{\text{period}}\) for each site-circuit unit). Column names for site and circuit match the resolved column names from the original sampling frame (or .circuit for designs without an explicit circuit column).

References

Jones, C. M., & Pollock, K. H. (2012). Recreational angler survey methods: estimation of effort, harvest, and released catch. In A. V. Zale, D. L. Parrish, & T. M. Sutton (Eds.), Fisheries Techniques (3rd ed., pp. 883–919). American Fisheries Society. \(\pi_i\) as used in Eq. 19.4 and 19.5.

Examples

sf <- data.frame(
  site = c("A", "B", "C"),
  p_site = c(0.3, 0.4, 0.3),
  p_period = rep(0.5, 3),
  stringsAsFactors = FALSE
)
cal <- data.frame(
  date = as.Date("2024-06-01"),
  day_type = "weekday",
  stringsAsFactors = FALSE
)
design <- creel_design(cal,
  date = date, strata = day_type,
  survey_type = "bus_route", sampling_frame = sf,
  site = site, p_site = p_site, p_period = p_period
)
get_inclusion_probs(design)
#>   site .circuit .pi_i
#> 1    A .default  0.15
#> 2    B .default  0.20
#> 3    C .default  0.15