diff --git a/src/App.js b/src/App.js
index bd66eae..519a403 100644
--- a/src/App.js
+++ b/src/App.js
@@ -6,6 +6,7 @@ import LoggedInHome from "./LoggedInHome";
 import Login from "./Login";
 import SetPage from "./SetPage";
 import GroupPage from "./GroupPage";
+import GroupStats from "./GroupStats";
 import UserGroups from "./UserGroups";
 import Settings from "./Settings";
 import Progress from "./Progress";
@@ -299,6 +300,9 @@ class App extends React.Component {
                 <Route path="/groups/:groupId" exact>
                   <GroupPage db={db} functions={functions} user={this.state.user} logEvent={analytics.logEvent} page={this.page} />
                 </Route>
+                <Route path="/groups/:groupId/stats" exact>
+                  <GroupStats db={db} user={this.state.user} logEvent={analytics.logEvent} page={this.page} />
+                </Route>
                 <Route path="/settings">
                   <Settings db={db} user={this.state.user} sound={this.state.sound} coloredEdges={this.state.coloredEdges} handleColoredEdgesChange={this.handleColoredEdgesChange} handleSoundChange={this.handleSoundChange} theme={this.state.theme} handleThemeChange={this.handleThemeChange} themes={themes} logEvent={analytics.logEvent} page={this.page} />
                 </Route>
@@ -371,7 +375,6 @@ class App extends React.Component {
             ></Button>
           </div>
         </Router>
-        {/* <div className="overlay"><img className="page-loader" src={Loader} alt="Loading..." /></div> */}
         <Fade out={!this.state.pageLoading && this.state.userDataPresent} className="page-loader-container">
           <img className="page-loader" src={Loader} alt="Loading..." />
         </Fade>
diff --git a/src/GroupPage.js b/src/GroupPage.js
index 362ae1d..1446c39 100644
--- a/src/GroupPage.js
+++ b/src/GroupPage.js
@@ -1,9 +1,11 @@
 import React, { Component } from 'react';
 import { withRouter, Link } from "react-router-dom";
-import { HomeRounded as HomeRoundedIcon, EditRounded as EditRoundedIcon, ArrowForwardRounded as ArrowForwardRoundedIcon, DeleteRounded as DeleteRoundedIcon } from "@material-ui/icons";
+import { TimelineRounded as TimelineRoundedIcon, HomeRounded as HomeRoundedIcon, EditRounded as EditRoundedIcon, ArrowForwardRounded as ArrowForwardRoundedIcon, DeleteRounded as DeleteRoundedIcon } from "@material-ui/icons";
 import NavBar from "./NavBar";
 import Button from "./Button";
+import LinkButton from "./LinkButton";
 import Footer from "./Footer";
+import Error404 from "./Error404";
 
 import "./css/GroupPage.css";
 import "./css/ConfirmationDialog.css";
@@ -55,70 +57,91 @@ export default withRouter(class GroupPage extends Component {
 		if (this.isMounted) super.setState(state, callback);
 	}
 
-	componentDidMount() {
-		this.state.db
-			.collection("users")
-			.doc(this.state.user.uid)
-			.collection("groups")
-			.doc(this.props.match.params.groupId)
-			.get()
-			.then((userGroupDoc) => {
-				this.state.db
-					.collection("groups")
-					.doc(this.props.match.params.groupId)
-					.get()
-					.then(async (groupDoc) => {
-						document.title = `${groupDoc.data().display_name} | Parandum`;
+	async componentDidMount() {
+		let promises = [];
+		let newState = {
+			sets: {},
+		};
 
-						let newState = {
-							role: userGroupDoc.data().role,
-							groupName: groupDoc.data().display_name,
-							originalGroupName: groupDoc.data().display_name,
-							sets: {},
-							memberCount: Object.keys(groupDoc.data().users).length + (Object.keys(groupDoc.data().users).includes(this.state.user.uid) ? 0 : 1),
-							joinCode: userGroupDoc.data().role === "owner" ? groupDoc.data().join_code : "",
-						};
+		promises.push(
+			this.state.db
+				.collection("users")
+				.doc(this.state.user.uid)
+				.collection("groups")
+				.doc(this.props.match.params.groupId)
+				.get()
+				.then((userGroupDoc) => userGroupDoc.data())
+				.catch((error) => {
+					console.log(`Can't access user group: ${error}`);
+					return {
+						role: "none",
+					};
+				})
+		);
 
-						await Promise.all(groupDoc.data().sets.map((setId) => {
-							return this.state.db.collection("sets")
-								.doc(setId)
-								.get()
-								.then((doc) => {
-									newState.sets[setId] = {
-										displayName: doc.data().title,
-										loading: false,
-									};
-								});
-						}));
+		promises.push(
+			this.state.db
+				.collection("groups")
+				.doc(this.props.match.params.groupId)
+				.get()
+				.then(async (groupDoc) => {
+					await Promise.all(groupDoc.data().sets.map((setId) => {
+						return this.state.db.collection("sets")
+							.doc(setId)
+							.get()
+							.then((doc) => {
+								newState.sets[setId] = {
+									displayName: doc.data().title,
+									loading: false,
+								};
+							});
+					}));
 
-						if (newState.role === "owner") {
-							const getGroupMembers = () => {
-								return this.state.functions.getGroupMembers({ groupId: this.props.match.params.groupId })
-									.catch((error) => {
-										return {
-											data: {
-												owners: [
-													{
-														displayName: this.state.user.displayName,
-														uid: this.state.user.uid,
-													}
-												],
-												contributors: [],
-												members: [],
-											}
-										}
-									});
-							}
+					return groupDoc.data();
+				}).catch((error) => {
+					console.log(`Can't access group: ${error}`);
+					return {
+						display_name: "",
+						users: {},
+						join_code: "",
+					};
+				})
+		);
 
-							const groupUsers = await getGroupMembers();
 
-							newState.groupUsers = groupUsers.data;
+		if (newState.role === "owner") {
+			promises.push(
+				this.state.functions.getGroupMembers({ groupId: this.props.match.params.groupId })
+					.then((response) => {
+						newState.groupUsers = response.data;
+					})
+					.catch((error) => {
+						newState.groupUsers = {
+							owners: [
+								{
+									displayName: this.state.user.displayName,
+									uid: this.state.user.uid,
+								}
+							],
+							contributors: [],
+							members: [],
 						}
+					})
+			)
+		}
 
-						this.setState(newState);
-						this.props.page.load();
-					});
-			});
+		const completedPromises = await Promise.all(promises);
+
+		document.title = `${completedPromises[1].display_name} | Parandum`;
+
+		newState.role = completedPromises[0].role;
+		newState.groupName = completedPromises[1].display_name;
+		newState.originalGroupName = completedPromises[1].display_name;
+		newState.memberCount = Object.keys(completedPromises[1].users).length + (Object.keys(completedPromises[1].users).includes(this.state.user.uid) ? 0 : 1);
+		newState.joinCode = completedPromises[0].role === "owner" ? completedPromises[1].join_code : "";
+
+		this.setState(newState);
+		this.props.page.load();
 
 		this.props.logEvent("select_content", {
 			content_type: "group",
@@ -336,6 +359,9 @@ export default withRouter(class GroupPage extends Component {
 
 	render() {
 		return (
+			(this.state.role === "none") ?
+			<Error404 />
+			:
 			<div>
 				<NavBar items={this.state.navbarItems} />
 				<main>
@@ -375,12 +401,20 @@ export default withRouter(class GroupPage extends Component {
 								}
 								{
 									this.state.role === "owner" &&
-									<Button
-										onClick={this.showDeleteGroup}
-										icon={<DeleteRoundedIcon />}
-										className="button--round"
-										title="Delete group"
-									></Button>
+									<div className="button-container">
+										<LinkButton
+											to={`/groups/${this.props.match.params.groupId}/stats`}
+											icon={<TimelineRoundedIcon />}
+											className="button--round"
+											title="Group progress"
+										></LinkButton>
+										<Button
+											onClick={this.showDeleteGroup}
+											icon={<DeleteRoundedIcon />}
+											className="button--round"
+											title="Delete group"
+										></Button>
+									</div>
 								}
 							</div>
 							{
diff --git a/src/GroupStats.js b/src/GroupStats.js
new file mode 100644
index 0000000..3fe9b75
--- /dev/null
+++ b/src/GroupStats.js
@@ -0,0 +1,237 @@
+import React, { Component } from 'react';
+import { GroupRounded as GroupRoundedIcon, HomeRounded as HomeRoundedIcon } from "@material-ui/icons";
+import { withRouter } from 'react-router-dom';
+import NavBar from "./NavBar";
+import Footer from "./Footer";
+import Error404 from "./Error404";
+import "./css/History.css";
+import "./css/MistakesHistory.css";
+
+export default withRouter(class GroupStats extends Component {
+	constructor(props) {
+		super(props);
+		this.state = {
+			user: props.user,
+			db: props.db,
+			navbarItems: [
+				{
+					type: "link",
+					link: `/groups/${this.props.match.params.groupId}`,
+					icon: <GroupRoundedIcon />,
+					hideTextMobile: true,
+				},
+				{
+					type: "link",
+					link: "/",
+					icon: <HomeRoundedIcon />,
+					hideTextMobile: true,
+				}
+			],
+			role: null,
+			groupName: "",
+		};
+
+		let isMounted = true;
+		Object.defineProperty(this, "isMounted", {
+			get: () => isMounted,
+			set: (value) => isMounted = value,
+		});
+	}
+
+	setState = (state, callback = null) => {
+		if (this.isMounted) super.setState(state, callback);
+	}
+
+	async componentDidMount() {
+		let promises = [];
+		let newState = {};
+
+		await this.state.db
+			.collection("users")
+			.doc(this.state.user.uid)
+			.collection("groups")
+			.doc(this.props.match.params.groupId)
+			.get()
+			.then((userGroupDoc) => {
+				newState.role = userGroupDoc.data().role;
+			})
+			.catch((error) => {
+				console.log(`Can't access user group: ${error}`);
+				newState.role = "none";
+			});
+
+		if (newState.role === "owner") {
+			promises.push(
+				this.state.db
+					.collection("groups")
+					.doc(this.props.match.params.groupId)
+					.get()
+					.then(async (groupDoc) => {
+						// await Promise.all(groupDoc.data().sets.map((setId) => {
+						// 	return this.state.db.collection("sets")
+						// 		.doc(setId)
+						// 		.get()
+						// 		.then((doc) => {
+						// 			newState.sets[setId] = {
+						// 				displayName: doc.data().title,
+						// 				loading: false,
+						// 			};
+						// 		});
+						// }));
+
+						document.title = `Stats | ${groupDoc.data().display_name} | Parandum`;
+						newState.groupName = groupDoc.data().display_name;
+					}).catch((error) => {
+						console.log(`Can't access group: ${error}`);
+						newState.groupName = "";
+						document.title = "Stats | Parandum";
+					})
+			);
+
+			promises.push(
+				this.state.db.collection("incorrect_answers")
+					.where("groups", "array-contains", this.props.match.params.groupId)
+					.orderBy("term", "asc")
+					.get()
+					.then((querySnapshot) => {
+						let incorrectAnswers = [];
+						querySnapshot.docs.map((doc, index, array) => {
+							if (index === 0 || doc.data().term !== array[index - 1].data().term || doc.data().definition !== array[index - 1].data().definition) {
+								incorrectAnswers.push({
+									term: doc.data().term,
+									definition: doc.data().definition,
+									answers: [{
+										answer: doc.data().answer,
+										switchLanguage: doc.data().switch_language,
+									}],
+									count: doc.data().switch_language ? 0 : 1,
+									switchedCount: doc.data().switch_language ? 1 : 0,
+								});
+							} else {
+								incorrectAnswers[incorrectAnswers.length - 1].answers.push({
+									answer: doc.data().answer,
+									switchLanguage: doc.data().switch_language,
+								});
+								if (doc.data().switch_language) {
+									incorrectAnswers[incorrectAnswers.length - 1].switchedCount++;
+								} else {
+									incorrectAnswers[incorrectAnswers.length - 1].count++;
+								}
+							}
+							return true;
+						});
+						newState.incorrectAnswers = incorrectAnswers.sort((a, b) => b.count + b.switchedCount - a.count - a.switchedCount);
+						newState.totalIncorrect = querySnapshot.docs.length;
+					})
+					.catch((error) => {
+						newState.incorrectAnswers = [];
+						newState.totalIncorrect = 0;
+						console.log(`Couldn't get group progress: ${error}`);
+					})
+			)
+
+			await Promise.all(promises);
+		}
+
+		this.setState(newState);
+		this.props.page.load();
+
+		this.props.logEvent("select_content", {
+			content_type: "group_stats",
+			item_id: this.props.match.params.groupId,
+		});
+	}
+
+	componentWillUnmount() {
+		this.isMounted = false;
+		this.props.page.unload();
+	}
+
+	render() {
+		return (
+			this.state.role !== null ?
+			(this.state.role === "owner"
+			?
+			<div>
+				<NavBar items={this.state.navbarItems} />
+				<main>
+					<h1>Group Stats: {this.state.groupName}</h1>
+					<div className="history-sections">
+						<div className="historical-user-stats-container">
+							<div className="stat-row stat-row--inline">
+								<h1>{this.state.totalIncorrect}</h1>
+								<p>mistakes</p>
+							</div>
+							{
+								this.state.incorrectAnswers.length > 0 &&
+								<div className="stat-row stat-row--inline">
+									<h1>{this.state.incorrectAnswers[0].term}</h1>
+									<p>meaning</p>
+									<h1>{this.state.incorrectAnswers[0].definition}</h1>
+									<p>is the most common</p>
+								</div>
+							}
+						</div>
+						<div className="mistakes-history-container">
+							{
+								this.state.incorrectAnswers.map((vocabItem, index) => (
+									<React.Fragment key={index}>
+										<div>
+											<h2>{vocabItem.term}</h2>
+											<p><b>{vocabItem.switchedCount} mistake{vocabItem.switchedCount !== 1 && "s"}{vocabItem.switchedCount > 0 && ":"}</b></p>
+											{
+												vocabItem.switchedCount > 0 &&
+												<div>
+													{
+														vocabItem.answers.sort((a, b) => {
+															if (a.answer < b.answer) {
+																return -1;
+															}
+															if (a.answer > b.answer) {
+																return 1;
+															}
+															return 0;
+														}).map((answerItem, index) => answerItem.switchLanguage && (
+															<p key={index}>{answerItem.answer === "" ? <i>skipped</i> : answerItem.answer}</p>
+														))
+													}
+												</div>
+											}
+										</div>
+										<div>
+											<h2>{vocabItem.definition}</h2>
+											<p><b>{vocabItem.count} mistake{vocabItem.count !== 1 && "s"}{vocabItem.count > 0 && ":"}</b></p>
+											{
+												vocabItem.count > 0 &&
+												<div>
+													{
+														vocabItem.answers.sort((a, b) => {
+															if (a.answer < b.answer) {
+																return -1;
+															}
+															if (a.answer > b.answer) {
+																return 1;
+															}
+															return 0;
+														}).map((answerItem, index) => !answerItem.switchLanguage && (
+															<p key={index}>{answerItem.answer === "" ? <i>skipped</i> : answerItem.answer}</p>
+														))
+													}
+												</div>
+											}
+										</div>
+									</React.Fragment>
+								))
+							}
+						</div>
+					</div>
+				</main>
+				<Footer />
+			</div>
+			:
+			<Error404 />)
+			:
+			null
+		)
+	}
+})