How to build a budgeting interface (sum of items must equal 100)?
I need the user to be able to change the ratios of items adding up to 100%. Essentially, I'm talking about an interactive pie chart, but even if such a thing existed, it would probably not be very usable (especially with a large number of slices), or accessible.
I currently have a vertical series of 0-100% sliders (with adjacent text field readout, also editable), with a dynamically updating total below, labeled "must be 100%". The form cannot be submitted until the total is 100%. There can be up to 14 items in the series.
Can anyone think of something better?