validation - Disabled submit button on form vs allow submit then show errors?

We have a few different forms as part of a web-based medical application. These forms have quite a few fields - 10-20 depending on the form. Each has at least 5 or so required fields. We currently disable the save button until those required fields are all completed.

We've been debating whether it's a better user experience to make the submit button enabled by default and then display an error message (and highlight missing required fields) if the submit button is clicked before all required fields are filled out.

Any research or sound opinions on what might be better? We're leaning towards the latter approach since our forms are pretty long -- allowing them to submit then find errors might be more efficient than the cognitive load of searching through the form to see why the button isn't enabled.

Answer

If the button is merely disabled, users will

1. Think the application is broken,


2. Not immediately realize which fields are unfilled and


3. Not realize the fields are unfilled until the very end, which is annoying

So, I'd suggest telling your colleagues exactly what you told us, which is that

allowing them to submit then find errors might be more efficient than the cognitive load of searching through the form to see why the button isn't enabled.