diff --git a/src/Maintained/Application/View/project.twig b/src/Maintained/Application/View/project.twig
index ef003bf..40223cc 100644
--- a/src/Maintained/Application/View/project.twig
+++ b/src/Maintained/Application/View/project.twig
@@ -16,7 +16,11 @@
                 <div class="col-lg-8 col-lg-offset-2 text-center">
 
                     <p>
-                        Resolution time: <strong>{{ resolutionTime.formatLong() }}</strong>
+                        Resolution time:
+                        <strong class="text-primary">{{ resolutionTime.formatLong() }}</strong>
+                    </p>
+                    <p class="small">
+                        The resolution time is the median time an issue stays open.
                     </p>
 
                 </div>
diff --git a/src/Maintained/Statistics/StatisticsComputer.php b/src/Maintained/Statistics/StatisticsComputer.php
index 0973e50..49b96f1 100644
--- a/src/Maintained/Statistics/StatisticsComputer.php
+++ b/src/Maintained/Statistics/StatisticsComputer.php
@@ -2,7 +2,9 @@
 
 namespace Maintained\Statistics;
 
-use Maintained\Diagnostic;
+use Github\Client;
+use Maintained\Issue;
+use Maintained\TimeInterval;
 
 /**
  * Computes statistics.
@@ -11,13 +13,109 @@ use Maintained\Diagnostic;
  */
 class StatisticsComputer implements StatisticsProvider
 {
+    /**
+     * @var Client
+     */
+    private $github;
+
+    public function __construct(Client $github)
+    {
+        $this->github = $github;
+    }
+
     public function getStatistics($user, $repository)
     {
-        $diagnostic = new Diagnostic($user . '/' . $repository);
+        $issues = $this->fetchIssues($user, $repository);
+        $collaborators = $this->fetchCollaborators($user, $repository);
+        $issues = $this->excludeIssuesCreatedByCollaborators($issues, $collaborators);
 
         $statistics = new Statistics();
-        $statistics->resolutionTime = $diagnostic->computeMedian();
+        $statistics->resolutionTime = $this->computeResolutionTime($issues);
 
         return $statistics;
     }
+
+    /**
+     * @param Issue[] $issues
+     * @return TimeInterval
+     */
+    private function computeResolutionTime(array $issues)
+    {
+        $durations = array_map(function (Issue $issue) {
+            return $issue->getOpenedFor()->toSeconds();
+        }, $issues);
+
+        return new TimeInterval($this->median($durations));
+    }
+
+    /**
+     * @param Issue[]  $issues
+     * @param string[] $collaborators
+     * @return Issue[]
+     */
+    private function excludeIssuesCreatedByCollaborators(array $issues, array $collaborators)
+    {
+        return array_filter($issues, function (Issue $issue) use ($collaborators) {
+            return !in_array($issue->getAuthor(), $collaborators);
+        });
+    }
+
+    /**
+     * @param float[] $array
+     * @return float
+     */
+    private function median(array $array) {
+        $count = count($array);
+
+        if ($count == 0) {
+            return 0;
+        }
+
+        sort($array, SORT_NUMERIC);
+
+        $middleIndex = (int) floor($count / 2);
+
+        // Handle the even case by averaging the middle 2 items
+        if ($count % 2 == 0) {
+            return ($array[$middleIndex] + $array[$middleIndex - 1]) / 2;
+        }
+
+        return $array[$middleIndex];
+    }
+
+    /**
+     * @param string $user
+     * @param string $repository
+     * @return Issue[]
+     */
+    private function fetchIssues($user, $repository)
+    {
+        /** @var \GitHub\Api\Issue $issueApi */
+        $issueApi = $this->github->api('issue');
+        $issues = $issueApi->all($user, $repository, ['state' => 'all']);
+
+        $issues = array_map(function (array $data) {
+            return Issue::fromArray($data);
+        }, $issues);
+
+        return $issues;
+    }
+
+    /**
+     * @param string $user
+     * @param string $repository
+     * @return string[]
+     */
+    private function fetchCollaborators($user, $repository)
+    {
+        /** @var \GitHub\Api\Repo $repositoryApi */
+        $repositoryApi = $this->github->api('repo');
+        $collaborators = $repositoryApi->collaborators()->all($user, $repository);
+
+        $collaborators = array_map(function ($user) {
+            return $user['login'];
+        }, $collaborators);
+
+        return $collaborators;
+    }
 }
diff --git a/src/Maintained/TimeInterval.php b/src/Maintained/TimeInterval.php
index 4ab9e4e..972bfb6 100644
--- a/src/Maintained/TimeInterval.php
+++ b/src/Maintained/TimeInterval.php
@@ -46,7 +46,7 @@ class TimeInterval
             case $this->seconds < self::TO_MINUTE:
                 return sprintf('%d s', $this->seconds);
             case $this->seconds < self::TO_HOUR:
-                return sprintf('%d m', $this->toMinutes());
+                return sprintf('%d min', $this->toMinutes());
             case $this->seconds < self::TO_DAY:
                 return sprintf('%d h', $this->toHours());
             default: