## NCA Software for R

The NCA software is free software that can be used with the free programming language R.

**======VERSION 4.0.1 is available======**

From version 4.0.0 the NCA software in R includes two new functions. The first is **nca_random** that generates a random dataset that meets a necessary condition with a given straight ceiling line. The function can be used for simulations with NCA. The second new function is **nca_power.** This function estimates the power of NCA's statistical test, which is the pre-study probability that the test will reject the null hypothesis when necessity exists. The function can be used to determine the minimum required sample size. Details of both functions can be found in https://bookdown.org/ncabook/advanced_nca2/statistical.html.

If you have installed an older version of the NCA package you can update the package as follows:

**update.packages("NCA")**

The NCA package uses other packages. It is possible that these packages are not installed on your computer. In that case the following error message may appear: 'There is no package called …' , where … corresponds to the name of the missing package. You then need to install the specific packages first.

**install.packages("…")**

If you install the package for the first time: see the Quick Start Guide. A novice user without knowledge of R or NCA can install the software on the user’s computer and perform an NCA analysis within 15 minutes.

The Quick Start Guide and a demonstration shows how NCA can be done in three steps.

The software draws ceiling lines and produces several NCA parameters (including necessity effect size). An example is shown here.

*A video *__explanation of the bottleneck table__* , and a video demonstration on how to produce the bottleneck table with the NCA software are available. *