diff --git a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing.xcodeproj/xcshareddata/xcbaselines/F3E26D942239409000AE182D.xcbaseline/122389AC-969F-420D-9EF1-1ED43478ED92.plist b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing.xcodeproj/xcshareddata/xcbaselines/F3E26D942239409000AE182D.xcbaseline/122389AC-969F-420D-9EF1-1ED43478ED92.plist
index 61ecbb8..443b6af 100644
--- a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing.xcodeproj/xcshareddata/xcbaselines/F3E26D942239409000AE182D.xcbaseline/122389AC-969F-420D-9EF1-1ED43478ED92.plist	
+++ b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing.xcodeproj/xcshareddata/xcbaselines/F3E26D942239409000AE182D.xcbaseline/122389AC-969F-420D-9EF1-1ED43478ED92.plist	
@@ -11,7 +11,7 @@
 				<key>com.apple.XCTPerformanceMetric_WallClockTime</key>
 				<dict>
 					<key>baselineAverage</key>
-					<real>0.391</real>
+					<real>0.556</real>
 					<key>baselineIntegrationDisplayName</key>
 					<string>Local Baseline</string>
 				</dict>
diff --git a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Controllers/Home/HomeViewController.swift b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Controllers/Home/HomeViewController.swift
index 3eecfaa..0ef3401 100644
--- a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Controllers/Home/HomeViewController.swift	
+++ b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Controllers/Home/HomeViewController.swift	
@@ -10,10 +10,19 @@ import UIKit
 
 class HomeViewController: UITableViewController {
     lazy var playData = PlayData()
+    lazy var words = playData.filteredWords
+}
+
+
+// MARK: - Lifecycle
+
+extension HomeViewController {
     
     override func viewDidLoad() {
         super.viewDidLoad()
         // Do any additional setup after loading the view, typically from a nib.
+        
+        playData.applyCustomFilter({ $0.lowercased().contains("swift") })
     }
 }
 
@@ -22,12 +31,12 @@ class HomeViewController: UITableViewController {
 
 extension HomeViewController {
     override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
-        return playData.allWords.count
+        return words.count
     }
     
     override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
         let cell = tableView.dequeueReusableCell(withIdentifier: StoryboardID.TableView.cell, for: indexPath)
-        let word = playData.allWords[indexPath.row]
+        let word = words[indexPath.row]
         
         cell.textLabel?.text = word
         cell.detailTextLabel?.text = "\(playData.wordCounts.count(for: word)) counts"
diff --git a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Models/PlayData.swift b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Models/PlayData.swift
index 5a5e139..e07cd44 100644
--- a/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Models/PlayData.swift	
+++ b/39-ios-unit-testing/iOS Unit Testing/iOS Unit Testing/Models/PlayData.swift	
@@ -10,21 +10,41 @@ import Foundation
 
 class PlayData {
     private lazy var pathToWords = Bundle.main.path(forResource: "plays", ofType: "txt")
-
-    var wordCounts: NSCountedSet!
-
+    
+    var allWords: [String] = []
+    var wordsSortedByCount: [String] = []
+    private(set) var filteredWords: [String] = []
+    
+    var wordCounts: NSCountedSet! {
+        didSet {
+            wordCountsChanged()
+        }
+    }
+    
+    
     init() {
         loadWords()
+        filteredWords = allWords
     }
 }
 
+
+// MARK: - Core Methods
+
 extension PlayData {
-    var allWords: [String] {
-        return wordCounts.allObjects as! [String]
+    func applyCustomFilter(_ predicate: (_ word: String) -> Bool) {
+        filteredWords = allWords.filter(predicate)
+    }
+    
+    func setCountThreshold(_ minimumCount: Int) {
+        filteredWords = allWords.filter { wordCounts.count(for: $0) >= minimumCount }
     }
 }
 
 
+
+// MARK: - Private Helper Methods
+
 private extension PlayData {
     func loadWords() {
         guard let pathToWords = pathToWords else {
@@ -44,5 +64,13 @@ private extension PlayData {
             print("Error while parsing plays file:\n\n\(error.localizedDescription)")
         }
     }
+    
+    func wordCountsChanged() {
+        allWords = wordCounts.allObjects as! [String]
+        
+        wordsSortedByCount = allWords.sorted(by: {
+            wordCounts.count(for: $0) > wordCounts.count(for: $1)
+        })
+    }
 }
 
diff --git a/39-ios-unit-testing/iOS Unit Testing/iOS Unit TestingTests/iOS_Unit_TestingTests.swift b/39-ios-unit-testing/iOS Unit Testing/iOS Unit TestingTests/iOS_Unit_TestingTests.swift
index e70f7d9..1d08195 100644
--- a/39-ios-unit-testing/iOS Unit Testing/iOS Unit TestingTests/iOS_Unit_TestingTests.swift	
+++ b/39-ios-unit-testing/iOS Unit Testing/iOS Unit TestingTests/iOS_Unit_TestingTests.swift	
@@ -43,6 +43,23 @@ class iOS_Unit_TestingTests: XCTestCase {
             XCTAssertEqual(actual, expected, "\"\(word)\" did not have a count of \(count)")
         }
     }
+    
+    func testFilteredWords() {
+        let playData = PlayData()
+        
+        playData.applyCustomFilter({ $0.count >= 10 })
+        
+        var expected = 2047
+        var actual = playData.filteredWords.count
+        
+        XCTAssertEqual(actual, expected, "`filteredWords` did not have expeted count of \(expected)")
+        
+        playData.applyCustomFilter { $0.lowercased().contains("swift") }
+        
+        expected = 7
+        actual = playData.filteredWords.count
+        XCTAssertEqual(actual, expected, "`filteredWords` did not have expeted count of \(expected)")
+    }
 }