diff --git a/packages/optimizely-sdk/lib/optimizely/index.js b/packages/optimizely-sdk/lib/optimizely/index.js
index 01719e5ea..8c81d2347 100644
--- a/packages/optimizely-sdk/lib/optimizely/index.js
+++ b/packages/optimizely-sdk/lib/optimizely/index.js
@@ -136,10 +136,7 @@ Optimizely.prototype.activate = function (experimentKey, userId, attributes) {
         this.logger.log(LOG_LEVEL.DEBUG, shouldNotDispatchActivateLogMessage);
         return variationKey;
       }
-
-      // remove null values from attributes
-      attributes = this.__filterEmptyValues(attributes);
-
+      
       this._sendImpressionEvent(experimentKey, variationKey, userId, attributes);
 
       return variationKey;
@@ -238,8 +235,7 @@ Optimizely.prototype.track = function(eventKey, userId, attributes, eventTags) {
         return;
       }
 
-      // remove null values from attributes and eventTags
-      attributes = this.__filterEmptyValues(attributes);
+      // remove null values from eventTags      
       eventTags = this.__filterEmptyValues(eventTags);
 
       var conversionEventOptions = {