diff --git a/client/app/controllers/tableController.js b/client/app/controllers/tableController.js
index e55f2aac..56e6174e 100644
--- a/client/app/controllers/tableController.js
+++ b/client/app/controllers/tableController.js
@@ -1,4 +1,4 @@
-define(['jquery', 'Handsontable', 'table_template', 'filesaver', 'alertify', 'qtip'], function ($, Handsontable, table_template, filesaver, alertify) {
+define(['jquery','controllers/usabilityController', 'Handsontable', 'table_template', 'filesaver', 'alertify', 'qtip'], function ($, usabilityController, Handsontable, table_template, filesaver, alertify) {
 
   'use strict';
 
@@ -567,11 +567,13 @@ define(['jquery', 'Handsontable', 'table_template', 'filesaver', 'alertify', 'qt
       beforeChange: function (changes, source) {
         return !(this.readOnly);
       },
-      afterSetDataAtCell: function (changes, source) {
-        //update_width(this);
-      },
-      afterChange: function (row, column) {
-        //update_width(this);
+      afterSetDataAtCell: function (changes) {
+        var cellInput = changes[0][3];
+        if (cellInput === '') {
+          usabilityController.addValidationError('EMPTY_CELL');
+        } else if (isNaN(parseInt(cellInput))) {
+          usabilityController.addValidationError('INVALID_CELL');
+        }
       }
     };
 
diff --git a/client/app/controllers/usabilityController.js b/client/app/controllers/usabilityController.js
index bfac60ad..83fe672b 100644
--- a/client/app/controllers/usabilityController.js
+++ b/client/app/controllers/usabilityController.js
@@ -79,6 +79,10 @@ define(['table_template'], function (table_template) {
   }
 
   function addValidationError(err) {
+
+    if (analytics.validation_errors[err] === undefined) {
+      return;
+    }
     analytics.validation_errors[err] += 1;
   }
 
diff --git a/client/app/data/pacesetters.js b/client/app/data/pacesetters.js
index 3008be2e..f746e157 100644
--- a/client/app/data/pacesetters.js
+++ b/client/app/data/pacesetters.js
@@ -221,8 +221,8 @@ define([], function () {
         'GENERIC_TABLE_ERR', 
         'SERVER_ERR', 
         'GENERIC_SUBMISSION_ERR',
-        'NAN_EMPTY_CELLS', 
-        'SEMANTIC_CELLS',
+        'EMPTY_CELL',
+        'INVALID_CELL',
         'CELL_ERROR'
         ]
       }