diff --git a/build/test.min.js b/build/test.min.js
index ea5fa3e..cc76081 100644
--- a/build/test.min.js
+++ b/build/test.min.js
@@ -1 +1 @@
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+!function(e){if("object"==typeof exports&&"undefined"!=typeof module)module.exports=e();else if("function"==typeof define&&define.amd)define([],e);else{var t;t="undefined"!=typeof window?window:"undefined"!=typeof global?global:"undefined"!=typeof self?self:this,t.Test=e()}}(function(){return function e(t,n,r){function o(a,u){if(!n[a]){if(!t[a]){var c="function"==typeof require&&require;if(!u&&c)return c(a,!0);if(i)return i(a,!0);var s=new Error("Cannot find module '"+a+"'");throw s.code="MODULE_NOT_FOUND",s}var f=n[a]={exports:{}};t[a][0].call(f.exports,function(e){var n=t[a][1][e];return o(n?n:e)},f,f.exports,e,t,n,r)}return n[a].exports}for(var i="function"==typeof require&&require,a=0;a<r.length;a++)o(r[a]);return o}({1:[function(e,t,n){"use strict";t.exports=e("./lib")["default"]},{"./lib":2}],2:[function(e,t,n){"use strict";function r(e){return e&&e.__esModule?e:{"default":e}}function o(e,t){if(!(e instanceof t))throw new TypeError("Cannot call a class as a function")}Object.defineProperty(n,"__esModule",{value:!0});var i=function(){function e(e,t){var n=[],r=!0,o=!1,i=void 0;try{for(var a,u=e[Symbol.iterator]();!(r=(a=u.next()).done)&&(n.push(a.value),!t||n.length!==t);r=!0);}catch(c){o=!0,i=c}finally{try{!r&&u["return"]&&u["return"]()}finally{if(o)throw i}}return n}return function(t,n){if(Array.isArray(t))return t;if(Symbol.iterator in Object(t))return e(t,n);throw new TypeError("Invalid attempt to destructure non-iterable instance")}}(),a=function(){function e(e,t){for(var n=0;n<t.length;n++){var r=t[n];r.enumerable=r.enumerable||!1,r.configurable=!0,"value"in r&&(r.writable=!0),Object.defineProperty(e,r.key,r)}}return function(t,n,r){return n&&e(t.prototype,n),r&&e(t,r),t}}(),u=e("../vendor/storage"),c=r(u),s=e("../vendor/camelize"),f=r(s),l=e("../vendor/get-param"),d=r(l),v="classList"in document.createElement("_"),p="ab-tests",h=function(){function e(t){var n=arguments.length>1&&void 0!==arguments[1]?arguments[1]:{},r=arguments.length>2&&void 0!==arguments[2]?arguments[2]:{};if(o(this,e),r={persist:"undefined"==typeof r.persist||r.persist,active:"undefined"==typeof r.active||r.active,chosen:"undefined"!=typeof r.chosen&&r.chosen},!t)throw new Error("Tests must have a name");if(!r.active)return{active:!1};var a=c["default"].local.getItem(p);if(a)try{a=JSON.parse(a)}catch(u){a={}}else a={};var s=void 0,l=((0,d["default"])("assign")||"").split(":"),h=i(l,2),g=h[0],y=h[1],m=g===t,w=y in n,b=r.persist&&a[t],O=m&&w||!b;if(console.log(O,b),O){for(var _=Object.keys(n),k=[],S=0;S<_.length;S++)"undefined"==typeof n[_[S]].weight&&(n[_[S]].weight=1),k.push(n[_[S]].weight);s=m&&w?y:e.chooseWeightedItem(_,k),a[t]={bucket:s,buckets:Object.keys(n)},c["default"].local.setItem(p,JSON.stringify(a))}else s=a[t].bucket;var x=t+"--"+s;v?document.body.classList.add(x):document.body.className+=" "+x;var I={bucket:s,data:n[s],active:!0};if(n[s]&&(n[s].chosen||(n[s].chosen=e.noop),n[s].chosen.call(this)),r.chosen&&r.chosen.call(this,I),"undefined"!=typeof dataLayer){var T={abTests:{}};T.abTests[(0,f["default"])(t)]=s,dataLayer.push(T)}return I}return a(e,null,[{key:"chooseWeightedItem",value:function(t,n){var r,o=0;for(r=0;r<n.length;r++)o+=n[r];var i=0,a=e.rand(0,o);for(r=0;r<t.length;r++)if(i+=n[r],a<=i)return t[r]}},{key:"noop",value:function(){}},{key:"rand",value:function(e,t){return Math.random()*(t-e)+e}}]),e}();n["default"]=h},{"../vendor/camelize":3,"../vendor/get-param":4,"../vendor/storage":5}],3:[function(e,t,n){"use strict";function r(e){return e.replace(o,function(e,t,n){return n?n.toUpperCase():""}).replace(i,function(e,t,n){return e.toLowerCase()})}Object.defineProperty(n,"__esModule",{value:!0}),n["default"]=r;var o=/(\-|\_|\.|\s)+(.)?/g,i=/(^|\/)([A-Z])/g},{}],4:[function(e,t,n){"use strict";function r(e,t){t||(t=window.location.href),e=e.replace(/[\[\]]/g,"\\$&");var n=new RegExp("[?&]"+e+"(=([^&#]*)|&|#|$)"),r=n.exec(t);return r?r[2]?decodeURIComponent(r[2].replace(/\+/g," ")):"":null}Object.defineProperty(n,"__esModule",{value:!0}),n["default"]=r},{}],5:[function(e,t,n){"use strict";function r(e){function t(e,t,n){var r=void 0,o=void 0;n?(r=new Date,r.setTime(r.getTime()+24*n*60*60*1e3),o="; 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\ No newline at end of file
diff --git a/lib/index.js b/lib/index.js
index e689451..bc7b8c5 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,13 +1,10 @@
 import storage from '../vendor/storage';
 import camelize from '../vendor/camelize';
+import getParam from '../vendor/get-param'
 
 const supportsClasslist = "classList" in document.createElement("_");
 const storageKey = 'ab-tests';
 
-function getParameterByName(name, url) {
-    if (!url) { url = window.location.href; } name = name.replace(/[\[\]]/g, "\\$&"); var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"), results = regex.exec(url); if (!results) return null; if (!results[2]) return ''; return decodeURIComponent(results[2].replace(/\+/g, " "));
-}
-
 class Test {
   constructor(name, data = {}, options = {}) {
     options = {
@@ -39,8 +36,19 @@ class Test {
 
     let bucket;
 
+    // Grab assignment via query param. Syntax:
+    // ?assign=test:bucket
+    const [assignTest, assignBucket]  = (getParam('assign') || '').split(':');
+    const assignmentMatchesName = assignTest === name;
+    const isValidBucket = assignBucket in data;
+
+    const useStoredAssignment = options.persist && tests[name];
+    const shouldAssign = (assignmentMatchesName && isValidBucket) || !useStoredAssignment;
+
+    console.log(shouldAssign, useStoredAssignment)
+
     // Retrieve Bucket from storage if possible
-    if (options.persist && tests[name]) {
+    if (!shouldAssign) {
       bucket = tests[name].bucket;
     }
 
@@ -56,12 +64,6 @@ class Test {
         weights.push( data[names[i]].weight );
       }
 
-      // Grab assignment via query param. Syntax:
-      // ?assign=test:bucket
-      const [assignTest, assignBucket]  = (getParameterByName('assign') || '').split(':');
-      const assignmentMatchesName = assignTest === name;
-      const isValidBucket = assignBucket in data;
-
       // Use query param assignment if possible
       if (assignmentMatchesName && isValidBucket) {
         bucket = assignBucket
diff --git a/package.json b/package.json
index d92846d..67c1d1e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "ab-tester",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "homepage": "https://github.com/dollarshaveclub/ab-tester.js",
   "main": "./index.js",
   "repository": {
diff --git a/vendor/get-param.js b/vendor/get-param.js
new file mode 100644
index 0000000..4eea391
--- /dev/null
+++ b/vendor/get-param.js
@@ -0,0 +1,9 @@
+
+export default function getParamByName(name, url) {
+    if (!url) { url = window.location.href; }
+    name = name.replace(/[\[\]]/g, "\\$&");
+    var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"), results = regex.exec(url);
+    if (!results) return null;
+    if (!results[2]) return '';
+    return decodeURIComponent(results[2].replace(/\+/g, " "));
+}