AngularJs access scope variable in another function

Okay, I see the problem. Your getClientIdentityDocuments_a() is using a callback function. THe asynchronous data retrieval happens seperately and so the value is not set by the time you want to use it. You can fix this by returning a promise

scope.getClientIdentityDocuments_a = function(clientID){
        var defer = $q.defer();  
        resourceFactory.clientResource.getAllClientDocuments(
                  {clientId: clientID, 
                   anotherresource: 'identifiers'}, function(data){
                scope.identityDocuments_a = data;
                defer.resolve(data);
            });            
            return defer.promise;
        };

and then, to use the data in your second function:

scope.getClientIdentityDocuments_a(scope.clientId).then(function(documents) {
       // at this point, the scope.identityDocuments_a should be available,
       // but you could just set it here, since the document variable is
       // returning the same thing
    console.dir(scope.identityDocuments_a) // should have the returned data
    console.dir(documents)                 // should be the same as above
});
// Here, the documents will NOT be available, because this executes before
// the promise is resolved
console.dir(scope.identityDocuments_a) // [] or undefined

UPDATE: To clarify, if in getClientIdentityDocuments_a you were to directly assign the variable, such as

scope.getClientIdentityDocuments_a = function(clientID){
        scope.identityDocuments_a = some_document;
};

You would not need the promise and your code would work. But since you are retrieving the data from an asynchronous source, your second function is trying to use the data before the value has been set.