precision: Precision calculations

In gmGeostats: Geostatistics for Compositional Analysis

Precision calculations

Description

Precision calculations

Usage

precision(x, ...)

## S3 method for class 'accuracy'
precision(x, ...)

Arguments

x	an object from which precision is to be computed
...	generic functionality, not used

Value

output depends on input and meaning of the function (the term precision is highly polysemic)

Methods (by class)

• accuracy: Compute precision and goodness for accuracy curves, after Deutsch (1997), using the accuracy curve obtained with accuracy(). This returns a named vector with two values, one for precision and one for goodness.

  Mean accuracy, precision and goodness were defined by Deutsch (1997) for an accuracy curve \{(p_i, \pi_i), i=1,2, \ldots, I\}, where \{p_i\} are a sequence of nominal confidence of prediction intervals and each \pi_i is the actual coverage of an interval with nominal confidence p_i. Out of these values, the mean accuracy (see mean.accuracy()) is computed as

  A = \int_{0}^{1} I\{(\pi_i-p_i)>0\} dp,

  where the indicator I\{(\pi_i-p_i)>0\} is 1 if the condition is satisfied and 0 otherwise. Out of it, the area above the 1:1 bisector and under the accuracy curve is the precision P = 1-2\int_{0}^{1} (\pi_i-p_i)\cdot I\{(\pi_i-p_i)>0\} dp, which only takes into account those points of the accuracy curve where \pi_i>p_i. To consider the whole curve, goodness can be used

  G = 1-\int_{0}^{1} (\pi_i-p_i)\cdot (3\cdot I\{(\pi_i-p_i)>0\}-2) dp.

See Also

Other accuracy functions: accuracy(), mean.accuracy(), plot.accuracy(), validate(), xvErrorMeasures.default(), xvErrorMeasures()

gmGeostats documentation built on April 18, 2023, 5:08 p.m.