The NCA Calculator calculates the necessary condition effect size and displays the scatter plot with a ceiling line. The calculator can be used in three steps:
- Select options. First, decide which ceiling line will be displayed in the scatter plot. If your data are discrete (the variables have two or more levels) select the option "discrete". The calculator will display the CE-FDH ceiling line (step function). If your data are continuous (the variables have a large number of levels up to infinity) select the option "continuous". The calculator will display the CR-FDH ceiling line (straight line). When the number of observations is small, you may consider to use the "discrete" option, even for continuous variables. Second, decide if you also want to display the Ordinariy Least Squares (OLS) regression line through the middle of the data, for reference.
- Enter data. By default the data window displays the data from an example, where Condition X is a country's Individualism and Outcome Y is a country's Innovation Performance. Each row is a case (country). For using your own data prepare a CSV file where rows correspond to cases, and columns correspond to the X and Y variables. The first row should contain headers (variable names). Upload your CSV file (Browse). When the data is uploaded a window appears where you can select your X variable (the condition) and your Y variable (the outcome) by entering the corresponding column number. The variable name appears in the box below the column number, and can be changed (this name is maintained during a calculator session; if you wish to recover the original variable name you must re-upload the CSV file). The variable names will be displayed at the X and Y axes of the scatter plot (see step 3). You can select the box "Use first columns for row names" to display row names in the data window. Select OK to show the new data in the data window.
- View results. Press the "View results" button to display the calculated effect size (d) and the scatter plot with the selected ceiling line and the OLS line if selected. The effect size can be compared with benchmark values. The effect size is one major NCA parameter for evaluating necessary conditions. Other parameters can be calculated with the NCA Software.
You can repeat the analysis with other variables by clicking "Change X and Y selection" under "Enter data"