Trim a panel to a balanced rectangle

Reduces a panel to a balanced set: a block of years in which every retained organization is observed in every retained year. Balancing trims (drops organizations and/or years) – the complement of panel_complete(), which fills gaps instead.

Usage

panel_balance(
  data,
  years = NULL,
  strategy = c("window", "max_rectangle"),
  min_years = 2L,
  id = "EIN2",
  time = "TAX_YEAR"
)

Arguments

data

A panel data frame.

years

Candidate years. NULL uses the full observed range.

strategy

"window" (default) or "max_rectangle".

min_years

Minimum number of years a balanced block must span.

id

Panel-ID column.

time

Panel-time column.

Value

The balanced rows, with a "balance" attribute listing the retained years and the organization keep/drop counts.

Details

The year window is the trade-off lever. A wide window keeps more years but fewer organizations; a narrow one keeps more organizations. Two strategies:

"window"

Balance over years (or, by default, the full observed range): keep only organizations observed in every one of those years, and drop the other years.

"max_rectangle"

Search contiguous year windows (within years if given) and pick the one that maximizes retained observations (organizations x years), subject to min_years.

See also

panel_complete(), panel_filter(), panel_describe().