diff --git a/wp-admin/edit-comments.php b/wp-admin/edit-comments.php
index a3c6e2bc3e..c89af54eb0 100644
--- a/wp-admin/edit-comments.php
+++ b/wp-admin/edit-comments.php
@@ -95,7 +95,7 @@ if ( isset($_REQUEST['doaction']) ||  isset($_REQUEST['doaction2']) || isset($_R
 
 	wp_redirect( $redirect_to );
 	exit;
-} elseif ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+} elseif ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
@@ -107,7 +107,7 @@ else
 
 require_once('admin-header.php');
 
-$mode = ( ! isset($_GET['mode']) || empty($_GET['mode']) ) ? 'detail' : esc_attr($_GET['mode']);
+$mode = ( empty($_GET['mode']) ) ? 'detail' : esc_attr($_GET['mode']);
 
 $comment_status = isset($_REQUEST['comment_status']) ? $_REQUEST['comment_status'] : 'all';
 if ( !in_array($comment_status, array('all', 'moderated', 'approved', 'spam', 'trash')) )
diff --git a/wp-admin/edit-link-categories.php b/wp-admin/edit-link-categories.php
index 5759880f91..cf6caa3b36 100644
--- a/wp-admin/edit-link-categories.php
+++ b/wp-admin/edit-link-categories.php
@@ -40,7 +40,7 @@ if ( isset($_GET['action']) && isset($_GET['delete']) ) {
 		wp_redirect($location);
 		exit();
 	}
-} elseif ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+} elseif ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
diff --git a/wp-admin/edit-tags.php b/wp-admin/edit-tags.php
index 4c29a707dd..65642881d6 100644
--- a/wp-admin/edit-tags.php
+++ b/wp-admin/edit-tags.php
@@ -155,7 +155,7 @@ break;
 
 default:
 
-if ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+if ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
diff --git a/wp-admin/edit.php b/wp-admin/edit.php
index dee7727692..2db1998474 100644
--- a/wp-admin/edit.php
+++ b/wp-admin/edit.php
@@ -132,7 +132,7 @@ if ( isset($_GET['doaction']) || isset($_GET['doaction2']) || isset($_GET['delet
 
 	wp_redirect($sendback);
 	exit();
-} elseif ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+} elseif ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
diff --git a/wp-admin/includes/class-wp-filesystem-ftpext.php b/wp-admin/includes/class-wp-filesystem-ftpext.php
index a5866b7204..4dff80b3e4 100644
--- a/wp-admin/includes/class-wp-filesystem-ftpext.php
+++ b/wp-admin/includes/class-wp-filesystem-ftpext.php
@@ -45,7 +45,7 @@ class WP_Filesystem_FTPext extends WP_Filesystem_Base {
 		else
 			$this->options['hostname'] = $opt['hostname'];
 
-		if ( isset($opt['base']) && ! empty($opt['base']) )
+		if ( ! empty($opt['base']) )
 			$this->wp_base = $opt['base'];
 
 		// Check if the options provided are OK.
diff --git a/wp-admin/includes/class-wp-filesystem-ftpsockets.php b/wp-admin/includes/class-wp-filesystem-ftpsockets.php
index c38bb295dd..efd19d1f6f 100644
--- a/wp-admin/includes/class-wp-filesystem-ftpsockets.php
+++ b/wp-admin/includes/class-wp-filesystem-ftpsockets.php
@@ -39,7 +39,7 @@ class WP_Filesystem_ftpsockets extends WP_Filesystem_Base {
 		else
 			$this->options['hostname'] = $opt['hostname'];
 
-		if ( isset($opt['base']) && ! empty($opt['base']) )
+		if ( ! empty($opt['base']) )
 			$this->wp_base = $opt['base'];
 
 		// Check if the options provided are OK.
diff --git a/wp-admin/includes/class-wp-filesystem-ssh2.php b/wp-admin/includes/class-wp-filesystem-ssh2.php
index a3f5660a1e..f5a64021cd 100644
--- a/wp-admin/includes/class-wp-filesystem-ssh2.php
+++ b/wp-admin/includes/class-wp-filesystem-ssh2.php
@@ -73,7 +73,7 @@ class WP_Filesystem_SSH2 extends WP_Filesystem_Base {
 		else
 			$this->options['hostname'] = $opt['hostname'];
 
-		if ( isset($opt['base']) && ! empty($opt['base']) )
+		if ( ! empty($opt['base']) )
 			$this->wp_base = $opt['base'];
 
 		// Check if the options provided are OK.
diff --git a/wp-admin/includes/plugin.php b/wp-admin/includes/plugin.php
index 901aa8e371..87b727fa3e 100644
--- a/wp-admin/includes/plugin.php
+++ b/wp-admin/includes/plugin.php
@@ -1243,9 +1243,8 @@ function get_admin_page_title() {
 	global $pagenow;
 	global $plugin_page;
 
-	if ( isset( $title ) && !empty ( $title ) ) {
+	if ( ! empty ( $title ) )
 		return $title;
-	}
 
 	$hook = get_plugin_page_hook( $plugin_page, $pagenow );
 
@@ -1290,7 +1289,7 @@ function get_admin_page_title() {
 				}
 			}
 		}
-		if ( !isset($title) || empty ( $title ) ) {
+		if ( empty ( $title ) ) {
 			foreach ( $menu as $menu_array ) {
 				if ( isset( $plugin_page ) &&
 					($plugin_page == $menu_array[2] ) &&
diff --git a/wp-admin/install.php b/wp-admin/install.php
index 94509fe8ba..8b68abc019 100644
--- a/wp-admin/install.php
+++ b/wp-admin/install.php
@@ -79,7 +79,7 @@ function display_setup_form( $error = null ) {
 
 	// Ensure that Blogs appear in search engines by default
 	$blog_public = 1;
-	if ( isset( $_POST ) && ! empty( $_POST ) )
+	if ( ! empty( $_POST ) )
 		$blog_public = isset( $_POST['blog_public'] );
 
 	$weblog_title = isset( $_POST['weblog_title'] ) ? trim( stripslashes( $_POST['weblog_title'] ) ) : '';
diff --git a/wp-admin/link-manager.php b/wp-admin/link-manager.php
index 90279dcb31..94b916e91c 100644
--- a/wp-admin/link-manager.php
+++ b/wp-admin/link-manager.php
@@ -28,7 +28,7 @@ if ( isset($_GET['action']) && isset($_GET['linkcheck']) ) {
 		wp_safe_redirect( wp_get_referer() );
 		exit;
 	}
-} elseif ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+} elseif ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
diff --git a/wp-admin/menu-header.php b/wp-admin/menu-header.php
index 3583514944..4ded52b32c 100644
--- a/wp-admin/menu-header.php
+++ b/wp-admin/menu-header.php
@@ -54,14 +54,14 @@ function _wp_menu_output( $menu, $submenu, $submenu_as_parent = true ) {
 				$class[] = 'current';
 		}
 
-		if ( isset($item[4]) && ! empty($item[4]) )
+		if ( ! empty($item[4]) )
 			$class[] = $item[4];
 
 		$class = $class ? ' class="' . join( ' ', $class ) . '"' : '';
 		$tabindex = ' tabindex="1"';
-		$id = isset($item[5]) && ! empty($item[5]) ? ' id="' . preg_replace( '|[^a-zA-Z0-9_:.]|', '-', $item[5] ) . '"' : '';
+		$id = ! empty($item[5]) ? ' id="' . preg_replace( '|[^a-zA-Z0-9_:.]|', '-', $item[5] ) . '"' : '';
 		$img = '';
-		if ( isset($item[6]) && ! empty($item[6]) ) {
+		if ( ! empty($item[6]) ) {
 			if ( 'div' === $item[6] )
 				$img = '<br />';
 			else
diff --git a/wp-admin/upload.php b/wp-admin/upload.php
index ce2d1f4d99..493994f8bb 100644
--- a/wp-admin/upload.php
+++ b/wp-admin/upload.php
@@ -117,7 +117,7 @@ if ( isset($_GET['find_detached']) ) {
 
 	wp_redirect($location);
 	exit;
-} elseif ( isset($_GET['_wp_http_referer']) && ! empty($_GET['_wp_http_referer']) ) {
+} elseif ( ! empty($_GET['_wp_http_referer']) ) {
 	 wp_redirect( remove_query_arg( array('_wp_http_referer', '_wpnonce'), stripslashes($_SERVER['REQUEST_URI']) ) );
 	 exit;
 }
diff --git a/wp-content/themes/default/archive.php b/wp-content/themes/default/archive.php
index 70c2a8cec8..f84708488c 100644
--- a/wp-content/themes/default/archive.php
+++ b/wp-content/themes/default/archive.php
@@ -24,7 +24,7 @@ get_header();
 		<h2 class="pagetitle">Archive for <?php the_time('Y'); ?></h2>
 	  <?php /* If this is an author archive */ } elseif (is_author()) { ?>
 		<h2 class="pagetitle">Author Archive</h2>
- 	  <?php /* If this is a paged archive */ } elseif (isset($_GET['paged']) && !empty($_GET['paged'])) { ?>
+ 	  <?php /* If this is a paged archive */ } elseif ( !empty($_GET['paged']) ) { ?>
 		<h2 class="pagetitle">Blog Archives</h2>
  	  <?php } ?>
 
diff --git a/wp-content/themes/default/sidebar.php b/wp-content/themes/default/sidebar.php
index 892d57409a..9f8990af11 100644
--- a/wp-content/themes/default/sidebar.php
+++ b/wp-content/themes/default/sidebar.php
@@ -42,7 +42,7 @@
 			<p>You have searched the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives
 			for <strong>'<?php the_search_query(); ?>'</strong>. If you are unable to find anything in these search results, you can try one of these links.</p>
 
-			<?php /* If this set is paginated */ } elseif (isset($_GET['paged']) && !empty($_GET['paged'])) { ?>
+			<?php /* If this set is paginated */ } elseif ( !empty($_GET['paged']) ) { ?>
 			<p>You are currently browsing the <a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a> blog archives.</p>
 
 			<?php } ?>
diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index d0f6d6c523..6a5abe2f5d 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -951,7 +951,7 @@ function wp_kses_bad_protocol_once2($matches) {
 	global $_kses_allowed_protocols;
 
 	if ( is_array($matches) ) {
-		if ( ! isset($matches[1]) || empty($matches[1]) )
+		if ( empty($matches[1]) )
 			return '';
 
 		$string = $matches[1];
diff --git a/wp-includes/load.php b/wp-includes/load.php
index 1a2e91d936..06a6ad9b74 100644
--- a/wp-includes/load.php
+++ b/wp-includes/load.php
@@ -62,7 +62,7 @@ function wp_fix_server_vars() {
 			}
 
 			// Append the query string if it exists and isn't null
-			if ( isset( $_SERVER['QUERY_STRING'] ) && !empty( $_SERVER['QUERY_STRING'] ) ) {
+			if ( ! empty( $_SERVER['QUERY_STRING'] ) ) {
 				$_SERVER['REQUEST_URI'] .= '?' . $_SERVER['QUERY_STRING'];
 			}
 		}
diff --git a/wp-includes/post-template.php b/wp-includes/post-template.php
index cd5fa5cb8a..b4189c9b9a 100644
--- a/wp-includes/post-template.php
+++ b/wp-includes/post-template.php
@@ -828,7 +828,7 @@ function wp_page_menu( $args = array() ) {
 	$list_args = $args;
 
 	// Show Home in the menu
-	if ( isset($args['show_home']) && ! empty($args['show_home']) ) {
+	if ( ! empty($args['show_home']) ) {
 		if ( true === $args['show_home'] || '1' === $args['show_home'] || 1 === $args['show_home'] )
 			$text = __('Home');
 		else
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 5313d14dc4..9a9acb03a4 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -2078,7 +2078,7 @@ function wp_insert_post($postarr = array(), $wp_error = false) {
 
 	// Create a valid post name.  Drafts and pending posts are allowed to have an empty
 	// post name.
-	if ( !isset($post_name) || empty($post_name) ) {
+	if ( empty($post_name) ) {
 		if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
 			$post_name = sanitize_title($post_title);
 		else
diff --git a/wp-includes/query.php b/wp-includes/query.php
index 9e684dfbf9..7bd75e49d3 100644
--- a/wp-includes/query.php
+++ b/wp-includes/query.php
@@ -2234,7 +2234,7 @@ class WP_Query {
 		if ( ! empty($q['meta_key']) )
 			$where .= $wpdb->prepare(" AND $wpdb->postmeta.meta_key = %s ", $q['meta_key']);
 		if ( ! empty($q['meta_value']) ) {
-			if ( ! isset($q['meta_compare']) || empty($q['meta_compare']) || ! in_array($q['meta_compare'], array('=', '!=', '>', '>=', '<', '<=')) )
+			if ( empty($q['meta_compare']) || ! in_array($q['meta_compare'], array('=', '!=', '>', '>=', '<', '<=')) )
 				$q['meta_compare'] = '=';
 
 			$where .= $wpdb->prepare("AND $wpdb->postmeta.meta_value {$q['meta_compare']} %s ", $q['meta_value']);
diff --git a/wp-includes/widgets.php b/wp-includes/widgets.php
index b213519d87..259eda4d90 100644
--- a/wp-includes/widgets.php
+++ b/wp-includes/widgets.php
@@ -966,7 +966,7 @@ function is_dynamic_sidebar() {
 function is_active_sidebar( $index ) {
 	$index = ( is_int($index) ) ? "sidebar-$index" : sanitize_title($index);
 	$sidebars_widgets = wp_get_sidebars_widgets();
-	if ( isset($sidebars_widgets[$index]) && !empty($sidebars_widgets[$index]) )
+	if ( !empty($sidebars_widgets[$index]) )
 		return true;
 
 	return false;