Extract per-site effort contributions from a bus-route estimate

Returns the per-site calculation table (\(e_i\), \(\pi_i\), \(e_i/\pi_i\)) stored as an attribute on effort estimate objects returned by estimate_effort() for bus-route survey designs. This table enables traceability of the Horvitz-Thompson estimator (Jones & Pollock 2012, Eq. 19.4) and supports validation against published examples (Malvestuto 1996, Box 20.6).

Usage

get_site_contributions(x)

Arguments

x

A creel_estimates object returned by estimate_effort() for a bus-route design.

Value

A tibble with columns:

site

Site identifier (from sampling frame)

circuit

Circuit identifier (from sampling frame)

e_i

Enumeration-expanded effort at site i (effort * expansion)

pi_i

Inclusion probability for site i (p_site * p_period)

e_i_over_pi_i

Site contribution to Horvitz-Thompson estimate

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.

See also

estimate_effort(), get_sampling_frame(), get_inclusion_probs(), get_enumeration_counts()

Other "Bus-Route Helpers": get_enumeration_counts(), get_inclusion_probs(), get_sampling_frame()

Examples

cal <- data.frame(
  date = as.Date(c("2024-06-03", "2024-06-04", "2024-06-05", "2024-06-06")),
  day_type = "weekday"
)
sf <- data.frame(
  site = c("A", "B"),
  circuit = c("am", "am"),
  p_site = c(0.6, 0.4),
  p_period = rep(0.5, 2)
)
design_br <- creel_design(
  cal,
  date = date, strata = day_type,
  survey_type = "bus_route", sampling_frame = sf,
  site = site, circuit = circuit,
  p_site = p_site, p_period = p_period
)
interviews <- data.frame(
  date = as.Date(c("2024-06-03", "2024-06-04")),
  site = c("A", "B"), circuit = c("am", "am"),
  catch_total = c(3L, 2L), hours_fished = c(2.0, 1.5),
  trip_status = c("complete", "complete"),
  trip_duration = c(2.0, 1.5),
  n_counted = c(5L, 4L), n_interviewed = c(3L, 2L)
)
design_br <- add_interviews(
  design_br, interviews,
  catch = catch_total, effort = hours_fished,
  trip_status = trip_status, trip_duration = trip_duration,
  n_counted = n_counted, n_interviewed = n_interviewed
)
#> Warning: ! No `n_anglers` provided — assuming 1 angler per interview.
#> ℹ Pass `n_anglers = <column>` to use actual party sizes for angler-hour
#>   normalization.
#> ℹ If the interviews really are one angler each, pass `n_anglers = 1` to state
#>   that and silence this warning.
#> Warning: 1 stratum has fewer than 3 interviews:
#> • Stratum weekday: 2 interviews
#> ! Sparse strata produce unstable variance estimates.
#> ℹ Consider combining sparse strata or collecting more data.
#> ℹ Repeats on this design are recorded, not printed: see `get_warnings()`.
#> ℹ Added 2 interviews: 2 complete (100%), 0 incomplete (0%)
result <- estimate_effort(design_br)
get_site_contributions(result)
#> # A tibble: 2 × 5
#>   site  circuit   e_i  pi_i e_i_over_pi_i
#>   <chr> <chr>   <dbl> <dbl>         <dbl>
#> 1 A     am       3.33   0.3          11.1
#> 2 B     am       3      0.2          15