Move a band specification onto another scale

The band presets are written on the scales survey work uses most: 1-5 for a rating, 0-10 for the Net Promoter answer, -100 to 100 for the score. Plenty of real questionnaires do not use those. Satisfaction is often collected on 0-100, and a seven-point agreement scale is common. rescale_bands() stretches a band specification onto the scale the chart is actually drawn on, so the thresholds can stay where they are instead of the data being divided to meet them.

Usage

rescale_bands(bands, to, from = NULL)

Arguments

bands

A band specification: one of bands_rating_3() and friends, or any data frame with from and to columns.

to

Length-2 numeric: the scale the chart uses, as c(min, max).

from

Length-2 numeric: the scale bands is written on. Read from the band edges themselves when omitted, which is what you want for the presets.

Value

bands with from and to moved onto the new scale. Labels and colours are untouched.

Details

The mapping is linear and proportional: a band covering the top fifth of its own scale covers the top fifth of the new one. Rescale rather than divide the data, so the axis a reader sees is still the scale the question was asked on.

See also

Other decisions: annotate_bands(), bands_rating_3(), mark_value()

Examples

# satisfaction collected 0-100, thresholds still where they belong
bands_rating_3() %>% rescale_bands(to = c(0, 100))
#>   label from  to  colour
#> 1   BAD    0  50 #FF3300
#> 2    OK   50  75 #FFCB3E
#> 3  GOOD   75 100 #86A33B

# a seven-point agreement scale
bands_rating_3() %>% rescale_bands(to = c(1, 7))
#>   label from  to  colour
#> 1   BAD  1.0 4.0 #FF3300
#> 2    OK  4.0 5.5 #FFCB3E
#> 3  GOOD  5.5 7.0 #86A33B