diff --git a/lib/registry.js b/lib/registry.js
index e658d43..f04b7ae 100644
--- a/lib/registry.js
+++ b/lib/registry.js
@@ -1,4 +1,5 @@
-var _ = require('underscore');
+const isEmpty = require('lodash.isempty');
+const isFunction = require('lodash.isfunction');
 
 //global collection of metrics.  Having this global makes it easy for other parts of application to access
 var _metrics;
@@ -9,13 +10,13 @@ function reset() {
 }
 
 function register(key, metric) {
-    if (_.isEmpty(metric)) {
+    if (isEmpty(metric)) {
         metric = key;
         key = null;
     }
 
     key = determineKey(key, metric);
-    if (_.isEmpty(key)) {
+    if (isEmpty(key)) {
         throw Error('Cannot register a metric without a key.  Key can be specified as a parameter, or supplied in the metric as name, name(), or getName()');
     }
 
@@ -24,11 +25,11 @@ function register(key, metric) {
 
 
     function determineKey(key, metric) {
-        if (_.isEmpty(key)) {
-            if (_.isFunction(metric.name)) {
+        if (isEmpty(key)) {
+            if (isFunction(metric.name)) {
                 key = metric.name();
             }
-            else if (_.isFunction(metric.getName)) {
+            else if (isFunction(metric.getName)) {
                 key = metric.getName();
             }
             else if (metric.name) {
@@ -45,7 +46,7 @@ function findOrCreate(metricname, constructor) {
         existingMetric = get(metricname);
     }
 
-    if (_.isEmpty(existingMetric)) {
+    if (isEmpty(existingMetric)) {
         var newMetric = new constructor(metricname);
         return register(newMetric);
     } else {
diff --git a/lib/statman.js b/lib/statman.js
index 03eee2e..1d3cb42 100644
--- a/lib/statman.js
+++ b/lib/statman.js
@@ -1,10 +1,8 @@
-var Stopwatch = module.exports.Stopwatch = require('statman-stopwatch');
-var Meter = module.exports.Meter = require('statman-meter');
-var Gauge = module.exports.Gauge = require('statman-gauge');
+const Stopwatch = module.exports.Stopwatch = require('statman-stopwatch');
+const Meter = module.exports.Meter = require('statman-meter');
+const Gauge = module.exports.Gauge = require('statman-gauge');
 
-var _ = require('underscore');
-
-var _registry = require('./registry');
+const _registry = require('./registry');
 
 // var httpFilters = require('./httpFilters');
 // exports.httpFilters = httpFilters;
diff --git a/package.json b/package.json
index 09e096d..fd7e4e0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "statman",
-  "version": "1.3.0",
+  "version": "1.4.0",
   "description": "Package to assist with collection of metrics, including stopwatch functionality",
   "main": "./lib/statman.js",
   "scripts": {
@@ -16,10 +16,12 @@
     "url": "https://github.com/jasonray/statman/issues"
   },
   "dependencies": {
+    "lodash.isempty": "^4.4.0",
+    "lodash.isfunction": "^3.0.9",
+    "lodash.isnull": "^3.0.0",
     "statman-gauge": "^1.0.5",
     "statman-meter": "^1.0.2",
-    "statman-stopwatch": "^2.4.0",
-    "underscore": "^1.8.3"
+    "statman-stopwatch": "^2.7.0"
   },
   "devDependencies": {
     "should": "^11.1.2",
diff --git a/test/gauge-test.js b/test/gauge-test.js
index ece8694..4a6a0bf 100644
--- a/test/gauge-test.js
+++ b/test/gauge-test.js
@@ -1,52 +1,52 @@
 /*jslint node: true */
 "use strict";
 
-var mocha = require('mocha');
-var assert = require('assert');
-var should = require('should');
-var statman = require('../lib/statman');
+const mocha = require('mocha');
+const assert = require('assert');
+const should = require('should');
+const statman = require('../lib/statman');
 
 describe('gauge (smoke test)', function () {
     it('gauagename', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         assert.equal('metric-name', gauge.name());
     });
 
     it('increment', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.increment();
         assert.equal(1, gauge.value());
     });
 
     it('incrementByValue', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.set(10);
         gauge.increment(2);
         assert.equal(12, gauge.value());
     });
 
     it('decrement', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.set(10);
         gauge.decrement();
         assert.equal(9, gauge.value());
     });
 
     it('decrementByValue', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.set(10);
         gauge.decrement(2);
         assert.equal(8, gauge.value());
     });
 
     it('set', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.set(5);
         assert.equal(5, gauge.value());
     });
 
     it('toString produces something with the value', function () {
-        var gauge = new statman.Gauge('metric-name');
+        const gauge = new statman.Gauge('metric-name');
         gauge.set(5);
         gauge.toString().should.containEql(5);
     });
diff --git a/test/meter-test.js b/test/meter-test.js
index b25bc12..b561733 100644
--- a/test/meter-test.js
+++ b/test/meter-test.js
@@ -1,28 +1,25 @@
 /*jslint node: true */
 "use strict";
 
-var statman = require('../lib/statman');
-var should = require('should');
+const statman = require('../lib/statman');
+const should = require('should');
 
 describe('meter (smoke test)', function () {
     this.timeout(5000);
 
     it('init should return an instance of meter', function () {
-        var meter;
-        meter = new statman.Meter();
+        const meter = new statman.Meter();
         should.exist(meter);
     });
 
     it('record once and get count should return 1', function () {
-        var meter;
-        meter = new statman.Meter();
+        const meter = new statman.Meter();
         meter.record();
         meter.getCount().should.be.equal(1);
     });
 
     it('record and read', function () {
-        var meter;
-        meter = new statman.Meter();
+        const meter = new statman.Meter();
         meter.record(1000);
         meter.record(2000);
         meter.getAverage().should.equal(1500);
@@ -30,9 +27,9 @@ describe('meter (smoke test)', function () {
     });
 
     it('meter.start() provides an event, which can be used to auto record meter', function (done) {
-        var meter = new statman.Meter();
+        const meter = new statman.Meter();
 
-        var meterEvent = meter.startEvent();
+        const meterEvent = meter.startEvent();
         setTimeout(function () {
             meterEvent.stop();
 
@@ -44,8 +41,7 @@ describe('meter (smoke test)', function () {
     });
 
     it('toString()', function () {
-        var meter;
-        meter = new statman.Meter();
+        const meter = new statman.Meter();
         meter.record(2.2);
         meter.record(4.4);
         meter.toString().should.equal('[count:2; average:3.30]');
diff --git a/test/statman-test.js b/test/statman-test.js
index 377f369..6922e40 100644
--- a/test/statman-test.js
+++ b/test/statman-test.js
@@ -1,6 +1,6 @@
-var statman = require('../lib/statman');
-var assert = require('assert');
-var should = require('should');
+const statman = require('../lib/statman');
+const assert = require('assert');
+const should = require('should');
 
 describe('registry', function () {
     beforeEach(function () {
@@ -8,9 +8,9 @@ describe('registry', function () {
     });
 
     it('registry() => returns full list of metrics', function () {
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -18,9 +18,9 @@ describe('registry', function () {
     });
 
     it('registry(name) => returns single item', function () {
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -30,11 +30,11 @@ describe('registry', function () {
     });
 
     it('registry can have key passed explicitly', function () {
-        var metric = {value: 'abc'};
+        const metric = {value: 'abc'};
 
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -44,11 +44,11 @@ describe('registry', function () {
     });
 
     it('registry can have key discovered from name', function () {
-        var metric = {name: 'x'};
+        const metric = {name: 'x'};
 
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -58,15 +58,15 @@ describe('registry', function () {
     });
 
     it('registry can have key discovered from name()', function () {
-        var metric = {
+        const metric = {
             name: function () {
                 return 'x'
             }
         };
 
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -76,15 +76,15 @@ describe('registry', function () {
     });
 
     it('registry can have key discovered from getName()', function () {
-        var metric = {
+        const metric = {
             getName: function () {
                 return 'x'
             }
         };
 
-        var metricA = {name: 'metricA'};
-        var metricB = {name: 'metricB'};
-        var metricC = {name: 'metric-C'};
+        const metricA = {name: 'metricA'};
+        const metricB = {name: 'metricB'};
+        const metricC = {name: 'metric-C'};
         statman.register(metricA);
         statman.register(metricB);
         statman.register(metricC);
@@ -94,12 +94,12 @@ describe('registry', function () {
     });
 
     it('registering metric with same name overwrites the first', function () {
-        var metricA = {
+        const metricA = {
             name: function () {
                 return 'metric-a'
             }, value: 1
         };
-        var metricB = {
+        const metricB = {
             name: function () {
                 return 'metric-a'
             }, value: 2
@@ -126,12 +126,12 @@ describe('registry', function () {
 
     describe('gauge in registry', function () {
         it('get new instance of a gauge', function () {
-            var gauge = statman.gauge('metric-name');
+            const gauge = statman.gauge('metric-name');
             gauge.name().should.equal('metric-name');
         });
 
         it('explicit register gauge', function () {
-            var gauge = new statman.Gauge('metric-name');
+            const gauge = new statman.Gauge('metric-name');
             should.not.exist(statman.registry('metric-name'));
             statman.register(gauge);
             should.exist(statman.registry('metric-name'));
@@ -155,12 +155,12 @@ describe('registry', function () {
 
     describe('meter in registry', function () {
         it('get new instance of a meter', function () {
-            var meter = statman.meter('metric-name');
+            const meter = statman.meter('metric-name');
             meter.name().should.equal('metric-name');
         });
 
         it('explicit register meter', function () {
-            var meter = new statman.Meter('metric-name');
+            const meter = new statman.Meter('metric-name');
             should.not.exist(statman.registry('metric-name'));
             statman.register(meter);
             should.exist(statman.registry('metric-name'));
diff --git a/test/stopwatch-test.js b/test/stopwatch-test.js
index 5618c36..4dee061 100644
--- a/test/stopwatch-test.js
+++ b/test/stopwatch-test.js
@@ -1,65 +1,64 @@
 /*jslint node: true */
 "use strict";
 
-var mocha = require('mocha');
-var assert = require('assert');
-var should = require('should');
-var statman = require('../lib/statman');
-var TestHelper = require('./testhelper');
-var _ = require('underscore');
+const mocha = require('mocha');
+const assert = require('assert');
+const should = require('should');
+const statman = require('../lib/statman');
+const verifyDelta = require('./testhelper').assertCloseEnough;
 
 describe('stopwatch (smoke test)', function () {
     beforeEach(function() {
        statman.reset();
     });
     it('explicit constructor', function () {
-        var stopwatch = new statman.Stopwatch('metric-name');
+        const stopwatch = new statman.Stopwatch('metric-name');
         should.exists(stopwatch);
     });
 
     it('explicit constructor (w/no name or autostart)', function () {
-        var stopwatch = new statman.Stopwatch();
+        const stopwatch = new statman.Stopwatch();
         should.exist(stopwatch.name());
     });
 
     it('explicit constructor (w/autostart)', function () {
-        var stopwatch = new statman.Stopwatch(true);
+        const stopwatch = new statman.Stopwatch(true);
         should.exist(stopwatch.name());
         stopwatch.name().should.not.equal(true);
     });
 
     it('explicit constructor (w/name and autostart)', function () {
-        var stopwatch = new statman.Stopwatch('metric-name', true);
+        const stopwatch = new statman.Stopwatch('metric-name', true);
         should.exist(stopwatch.name());
         stopwatch.name().should.equal('metric-name');
     });
 
     it('implicit constructor', function () {
-        var stopwatch = statman.stopwatch('metric-name');
+        const stopwatch = statman.stopwatch('metric-name');
         should.exists(stopwatch);
     });
 
     it('implicit constructor w/no name', function () {
-        var stopwatch = statman.stopwatch();
+        const stopwatch = statman.stopwatch();
         should.exists(stopwatch);
         should.exist(stopwatch.name());
     });
 
     it('name', function () {
-        var stopwatch = new statman.Stopwatch('metric-name');
+        const stopwatch = new statman.Stopwatch('metric-name');
         assert.equal('metric-name', stopwatch.name());
     });
 
     it('access via registry', function () {
-        var stopwatch = statman.stopwatch('metric-name');
+        const stopwatch = statman.stopwatch('metric-name');
         statman.registry('metric-name').start();
         statman.registry('metric-name').stop();
     });
 
     it('start and read (10ms)', function (done) {
-        var testtime = 10;
+        const testtime = 10;
 
-        var stopwatch = new statman.Stopwatch();
+        const stopwatch = new statman.Stopwatch();
         stopwatch.start();
         setTimeout(function () {
             var delta = stopwatch.read();
@@ -69,9 +68,9 @@ describe('stopwatch (smoke test)', function () {
     });
 
     it('autostart and read (10ms)', function (done) {
-        var testtime = 10;
+        const testtime = 10;
 
-        var stopwatch = new statman.Stopwatch(true);
+        const stopwatch = new statman.Stopwatch(true);
         setTimeout(function () {
             var delta = stopwatch.read();
             verifyDelta(testtime, delta, 10);
@@ -81,20 +80,20 @@ describe('stopwatch (smoke test)', function () {
 
     describe('toString()', function () {
         it('idle', function () {
-            var stopwatch = statman.stopwatch('sw');
+            const stopwatch = statman.stopwatch('sw');
             //[sw => state:init; value:NaN]
             stopwatch.toString().should.containEql('state:init');
             stopwatch.toString().should.containEql('value:');
         });
         it('started', function () {
-            var stopwatch = statman.stopwatch('sw');
+            const stopwatch = statman.stopwatch('sw');
             stopwatch.start();
             //[sw => state:running; value:0.01]
             stopwatch.toString().should.containEql('state:running');
             stopwatch.toString().should.containEql('value:');
         });
         it('stopped', function () {
-            var stopwatch = statman.stopwatch('sw');
+            const stopwatch = statman.stopwatch('sw');
             stopwatch.start();
             stopwatch.stop();
             //[sw => state:stopped; value:0.01]
@@ -102,13 +101,4 @@ describe('stopwatch (smoke test)', function () {
             stopwatch.toString().should.containEql('value:');
         });
     });
-});
-
-//TODO:
-//replace with: statman.TestHelper.assertCloseEnough(testtime, delta, defaultPrecision);
-function verifyDelta(expected, actual, acceptedVariance) {
-    var lowerThreshold = expected - acceptedVariance;
-    var upperThreshold = expected + acceptedVariance;
-    var message = "Expected " + expected + " ± " + acceptedVariance + ", was " + actual + ".";
-    assert.ok((actual >= lowerThreshold) && (actual <= upperThreshold), message);
-}
\ No newline at end of file
+});
\ No newline at end of file
diff --git a/test/testhelper.js b/test/testhelper.js
index fce61c4..49ce656 100644
--- a/test/testhelper.js
+++ b/test/testhelper.js
@@ -1,12 +1,11 @@
-var _ = require('underscore');
-var assert = require('assert');
-
+const assert = require('assert');
+const isNull = require('lodash.isnull');
 
 function assertCloseEnough(actual, expected, acceptedVariance) {
-    if (_.isNull(acceptedVariance)) acceptedVariance = 10;
-    var lowerThreshold = expected - acceptedVariance;
-    var upperThreshold = expected + acceptedVariance;
-    var message = "Expected " + expected + " ± " + acceptedVariance + ", was " + actual + ".";
+    if (isNull(acceptedVariance)) acceptedVariance = 10;
+    const lowerThreshold = expected - acceptedVariance;
+    const upperThreshold = expected + acceptedVariance;
+    const message = "Expected " + expected + " ± " + acceptedVariance + ", was " + actual + ".";
     assert.ok((actual >= lowerThreshold) && (actual <= upperThreshold), message);
 }