quickpsy is an R package developed by Daniel Linares and Joan López-Moliner to quickly fit and plot psychometric functions for multiple conditions.

You can find more information at the website.


You can install the released version of quickpsy from CRAN with:


And the development version from GitHub with:

# install.packages("devtools")

At present, the development version of quickpsy is slower than older versions. If you need to perform bootstrap for many conditions you might want to use an older version.



fit <- quickpsy(qpdat, phase, resp, grouping = c("participant", "cond"))

plot(fit, color = cond)


Development version (at present it is slower than the CRAN version)

  • Different conditions could share parameters.

  • Easy model comparisons using likelihood ratios or Akaike information criterion.


Linares, D., & López-Moliner, J. (2016). quickpsy: An R package to fit psychometric functions for multiple groups. The R Journal, 2016, vol. 8, num. 1, p. 122-131.

Other R packages to fit psychometric functions