ppod defines the proportion (baseline probability or rate) of a decision being positive (but not necessarily accurate/correct).

ppod

## Format

An object of class numeric of length 1.

## Details

Understanding or obtaining the proportion of positive decisions ppod:

• Definition: ppod is the (non-conditional) probability:

ppod = p(decision = positive)

or the base rate (or baseline probability) of a decision being positive (but not necessarily accurate/correct).

• Perspective: ppod classifies a population of N individuals by decision (ppod = dec_pos/N).

ppod is the "by decision" counterpart to prev (which adopts a "by condition" perspective).

• Alternative names: base rate of positive decisions (PR), proportion predicted or diagnosed, rate of decision = positive cases

• In terms of frequencies, ppod is the ratio of dec_pos (i.e., hi + fa) divided by N (i.e., hi + mi + fa + cr):

ppod = dec_pos/N = (hi + fa)/(hi + mi + fa + cr)

• Dependencies: ppod is a feature of the decision process or diagnostic procedure.

However, the conditional probabilities sens, mirt, spec, fart, PPV, and NPV also depend on the condition's prevalence prev.

prob contains current probability information; comp_prob computes current probability information; num contains basic numeric parameters; init_num initializes basic numeric parameters; freq contains current frequency information; comp_freq computes current frequency information; is_prob verifies probabilities.
Other probabilities: FDR, FOR, NPV, PPV, acc, err, fart, mirt, prev, sens, spec
ppod <- .50     # sets a rate of positive decisions of 50%