Using a variable to count the number of correct answers in a quiz

Hi Everyone,

I have been looking at threads with methods on how to create a quiz with several Multiple Choice Questions within one slide. My workaround has been to input a number of Radio Buttons and create relevant Button Sets so that the user can only choose one at a time, e.g. True or False or Cannot Say (I have attached the files for demonstration purposes).

To the best of my knowledge, Storyline would calculate just one score for my entire 'Pick Many' interaction rather than for each individual question (e.g. on pressing submit, Storyline would provide a score of 1 point if all 4 ques correct or  0 points if all 4 incorrect, whereas my task is to keep four questions on one slide but get a score for each question individually, i.e. a score out of 4).

Therefore, my workaround has been to create a variable called 'CorrectAnswerCounter' which adds the value of 1 when the user clicks to Submit the interaction on the condition that the correct radio button is selected for each of the four button sets. In this way, the variable counts each correct answer as 1 point which is exactly what I want.

The problem is that this quiz requires both a customised 'Previous' and 'Next' button. At the moment, clicking the 'Next' button activates the trigger to increase the 'CorrectAnswerCounter' variable by however many radio buttons are correctly selected. The variable 'CorrectAnswerCounter' works perfectly if the User just keeps pressing 'Next'. However, if the User presses the 'Previous' button to revisit a slide where they have already ready answered the questions and then presses 'Next' to move forward again (which submits the answer a second time), then my scores are doubled up at the end.

I've tried to counteract the problem by subtracting the value of 1 when a user clicks the 'Previous' button for however many radio buttons are correctlyn selected. However, this doesn't work as I would need to subtract the number of correct answers from the previous slide (rather than that current slide).

Is their any other solution besides removing the 'Previous' button altogether?

Sorry for the long post and would be very grateful for any advice.

All the best,

Laura