In my directive (in the link function) I had created scope variable success like this:
link: function(scope, element, attrs) {
"use strict";
scope.success = false;
And in the scope template included input tag like:
<input type="checkbox" ng-model="success">
This did not work.
In the end I changed my scope variable to look like this:
link: function(scope, element, attrs) {
"use strict";
scope.outcome = {
success : false
};
And my input tag to look like this:
<input type="checkbox" ng-model="outcome.success">
It now works as expected. I knew an explanation for this, but forgot, maybe someone will fill it in for me. :)