Reflect calculated value from one page to the next

[wcrescioni]

Hi Angelistine. I think I can help with this. It should be possible to achieve what you want using the "responses.xls" feature. Essentially, by placing an excel worksheet in the same folder as your experiment named "responses.xls", you can have MediaLab perform calculations on the fly based on user input. You can then feed the results of those calculations back into MediaLab to present them to the user.

Here's how it works. In the same folder in which you save your experiment, create an excel file. In the first three cells of the first row (A1, B1, and C1), put the following, respectively: variable, value, and skipto. Now, in the "variable" column, list all the variable names from your experiment that you want to use for calcultions (in your example, a1, b1, a2, b2, a3, and b3). MediaLab will fill in these values as the study runs. Once you listed everything out, you can actually create new variables in the file. To do so, just put a variable name in the "variable" that doesn't exist in your experiment (for example, if you wanted to create a running sum of participants scores on a personality measure, you might make a variable called "personalitySum").

Leave the "value" column blank for the variables that your going to base your calculations on. For the calculated values (C, in your example), just input an excel formula to do whatever calculation you'd like.

Now, when it comes time to show the participant the calculated value, just create an "instruction" item type. To have it show the calculated variable, enclose the variable name in <>. So, lets say your participants running total for "C" was 5. If you made an instruction item that read Current tally: <C>, then what they would see is "Current tally: 5.

It's probably easier to understand if you see it in action. I've included a .que, .exp, and responses.xls file that you can use as a template. MediaLab also comes with a sample in the Samples folders that shows this in action.

I hope this helps. I know it can seem a little complicated, so please let me know if I can be any further help.

Good luck and happy researching!