Change event on select with knockout binding, how can I know if it is a real change?

Actually you want to find whether the event is triggered by user or program , and its obvious that event will trigger while initialization.

The knockout approach of adding subscription won't help in all cases, why because in most of the model will be implemented like this

1. init the model with undefined data , just structure (actual KO initilization)
2. update the model with initial data (logical init like load JSON , get data etc)
3. User interaction and updates

The actual step that we want to capture is changes in 3, but in second step subscription will get call , So a better way is to add to event change like

 <select data-bind="value: level, event:{ change: $parent.permissionChanged}">

and detected the event in permissionChanged function

this.permissionChanged = function (obj, event) {

  if (event.originalEvent) { //user changed

  } else { // program changed

  }

}

This is just a guess, but I think it's happening because level is a number. In that case, the value binding will trigger a change event to update level with the string value. You can fix this, therefore, by making sure level is a string to start with.

Additionally, the more "Knockout" way of doing this is to not use event handlers, but to use observables and subscriptions. Make level an observable and then add a subscription to it, which will get run whenever level changes.