diff --git a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tab.tsx b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tab.tsx
index d17c0adf21..1a0a24f1e3 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tab.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tab.tsx
@@ -19,10 +19,10 @@ import { getPostDrivenTime } from "@/utils/questions/helpers";
 import ContinuousAggregationChart from "./continuous_aggregations_chart";
 import HistogramDrawer from "./histogram_drawer";
 import { AGGREGATION_EXPLORER_OPTIONS } from "../constants";
-import { AggregationQuestionWithBots } from "../types";
+import { AggregationExtraQuestion } from "../types";
 
 type Props = {
-  aggregationData: AggregationQuestionWithBots | null;
+  aggregationData: AggregationExtraQuestion | null;
   activeTab: string;
   selectedSubQuestionOption: number | string | null;
   postId: number;
@@ -42,7 +42,6 @@ const AggregationsTab: FC<Props> = ({
 
   const {
     aggregations,
-    bot_aggregations,
     actual_close_time,
     resolution,
     unit,
@@ -54,11 +53,8 @@ const AggregationsTab: FC<Props> = ({
     AGGREGATION_EXPLORER_OPTIONS[0];
 
   const activeAggregation = useMemo(
-    () =>
-      tabData?.includeBots
-        ? bot_aggregations?.[tabData.value]
-        : aggregations?.[tabData.value],
-    [aggregations, bot_aggregations, tabData]
+    () => aggregations?.[tabData.id],
+    [aggregations, tabData]
   );
 
   let aggregationIndex: number | undefined;
@@ -124,7 +120,7 @@ const AggregationsTab: FC<Props> = ({
     return null;
   }
 
-  const renderAggregation = (questionData: AggregationQuestionWithBots) => {
+  const renderAggregation = (questionData: AggregationExtraQuestion) => {
     switch (questionData.type) {
       case QuestionType.Binary:
         return (
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tooltip.tsx b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tooltip.tsx
index 5778be7f23..687d17c99f 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tooltip.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_tooltip.tsx
@@ -8,28 +8,25 @@ import ChoiceCheckbox from "@/components/choice_checkbox";
 import Button from "@/components/ui/button";
 import LoadingIndicator from "@/components/ui/loading_indicator";
 import { ChoiceItem } from "@/types/choices";
-import { AggregationMethod } from "@/types/question";
 import { ThemeColor } from "@/types/theme";
 import { logError } from "@/utils/core/errors";
 
-import { AggregationMethodWithBots } from "../types";
+import { AggregationExtraMethod } from "../types";
 
 type Props = {
   valueLabel: string;
   tooltips: {
-    aggregationMethod: AggregationMethod;
-    choice: AggregationMethodWithBots;
+    aggregationMethod: string;
+    choice: AggregationExtraMethod;
     label: string;
     includeBots: boolean;
     color: ThemeColor;
   };
-  onFetchData: (
-    aggregationOptionId: AggregationMethodWithBots
-  ) => Promise<void>;
+  onFetchData: (aggregationOptionId: AggregationExtraMethod) => Promise<void>;
   onChoiceChange: (choice: string, checked: boolean) => void;
   onChoiceHighlight: (choice: string, highlighted: boolean) => void;
   choiceItems: ChoiceItem[];
-  onTabChange: (activeTab: AggregationMethodWithBots) => void;
+  onTabChange: (activeTab: AggregationExtraMethod) => void;
 };
 
 const AggregationTooltip: FC<Props> = ({
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_wrapper.tsx b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_wrapper.tsx
index 043e406788..a1e5908e65 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/aggregation_wrapper.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/aggregation_wrapper.tsx
@@ -8,16 +8,14 @@ import { logError } from "@/utils/core/errors";
 import AggregationsTab from "./aggregation_tab";
 import AggregationsDrawer from "./aggregations_drawer";
 import { AGGREGATION_EXPLORER_OPTIONS } from "../constants";
-import {
-  AggregationMethodWithBots,
-  AggregationQuestionWithBots,
-} from "../types";
+import { AggregationExtraMethod, AggregationExtraQuestion } from "../types";
 
 type Props = {
-  activeTab: AggregationMethodWithBots | null;
-  onTabChange: (activeTab: AggregationMethodWithBots) => void;
+  activeTab: AggregationExtraMethod | null;
+  onTabChange: (activeTab: AggregationExtraMethod) => void;
   data: QuestionWithForecasts | PostWithForecasts;
   selectedSubQuestionOption: number | string | null;
+  joinedBeforeDate?: string;
   additionalParams?: {
     userIds?: number[]; // Array of user IDs as a comma-separated string
   };
@@ -28,22 +26,27 @@ export const AggregationWrapper: FC<Props> = ({
   onTabChange,
   selectedSubQuestionOption,
   data,
+  joinedBeforeDate,
   additionalParams = {},
 }) => {
   const postId = "post_id" in data ? data.post_id : data.id;
   const [selectedAggregationMethods, setSelectedAggregationMethods] = useState<
-    AggregationMethodWithBots[]
+    AggregationExtraMethod[]
   >([]);
   const [aggregationData, setAggregationData] =
-    useState<AggregationQuestionWithBots | null>(null);
+    useState<AggregationExtraQuestion | null>(null);
 
   const handleFetchAggregations = useCallback(
-    async (aggregationOptionId: AggregationMethodWithBots) => {
+    async (aggregationOptionId: AggregationExtraMethod) => {
       const aggregationOption =
         AGGREGATION_EXPLORER_OPTIONS.find(
           (option) => option.id === aggregationOptionId
         ) ?? AGGREGATION_EXPLORER_OPTIONS[0];
-      const { value: aggregationMethod, includeBots } = aggregationOption;
+      const {
+        value: methodName,
+        id: methodID,
+        includeBots,
+      } = aggregationOption;
 
       if (selectedAggregationMethods.includes(aggregationOptionId)) {
         return;
@@ -60,46 +63,23 @@ export const AggregationWrapper: FC<Props> = ({
           postId,
           questionId: adjustedQuestionId,
           includeBots,
-          aggregationMethods: aggregationMethod,
+          aggregationMethods: methodName,
+          joinedBeforeDate,
           ...additionalParams,
         });
 
-        const fetchedAggregationData = response.aggregations[aggregationMethod];
+        const fetchedAggregationData = response.aggregations[methodName];
         if (fetchedAggregationData !== undefined) {
-          setAggregationData((prev) =>
-            prev
-              ? ({
-                  ...prev,
-                  ...(includeBots
-                    ? {
-                        bot_aggregations: {
-                          ...prev.bot_aggregations,
-                          [aggregationMethod]: fetchedAggregationData,
-                        },
-                      }
-                    : {
-                        aggregations: {
-                          ...prev.aggregations,
-                          [aggregationMethod]: fetchedAggregationData,
-                        },
-                      }),
-                } as AggregationQuestionWithBots)
-              : ({
-                  ...response,
-                  ...(includeBots
-                    ? {
-                        bot_aggregations: {
-                          [aggregationMethod]: fetchedAggregationData,
-                        },
-                        aggregations: {},
-                      }
-                    : {
-                        aggregations: {
-                          [aggregationMethod]: fetchedAggregationData,
-                        },
-                      }),
-                } as AggregationQuestionWithBots)
-          );
+          setAggregationData((prev) => {
+            const base = prev ?? response;
+            return {
+              ...base,
+              aggregations: {
+                ...base.aggregations,
+                [methodID]: fetchedAggregationData,
+              },
+            } as AggregationExtraQuestion;
+          });
         }
         setSelectedAggregationMethods((prev) => [...prev, aggregationOptionId]);
       } catch (err) {
@@ -110,6 +90,7 @@ export const AggregationWrapper: FC<Props> = ({
       selectedAggregationMethods,
       selectedSubQuestionOption,
       postId,
+      joinedBeforeDate,
       additionalParams,
     ]
   );
@@ -129,6 +110,7 @@ export const AggregationWrapper: FC<Props> = ({
       onFetchData={handleFetchAggregations}
       aggregationData={aggregationData}
       selectedSubQuestionOption={selectedSubQuestionOption}
+      joinedBeforeDate={joinedBeforeDate}
     />
   );
 };
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/aggregations_drawer.tsx b/front_end/src/app/(main)/aggregation-explorer/components/aggregations_drawer.tsx
index 232ecbf4a4..7802752be7 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/aggregations_drawer.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/aggregations_drawer.tsx
@@ -27,18 +27,14 @@ import {
   generateAggregationTooltips,
   generateChoiceItemsFromAggregations,
 } from "../helpers";
-import {
-  AggregationMethodWithBots,
-  AggregationQuestionWithBots,
-} from "../types";
+import { AggregationExtraMethod, AggregationExtraQuestion } from "../types";
 
 type Props = {
-  onTabChange: (activeTab: AggregationMethodWithBots) => void;
-  onFetchData: (
-    aggregationOptionId: AggregationMethodWithBots
-  ) => Promise<void>;
-  aggregationData: AggregationQuestionWithBots | null;
+  onTabChange: (activeTab: AggregationExtraMethod) => void;
+  onFetchData: (aggregationOptionId: AggregationExtraMethod) => Promise<void>;
+  aggregationData: AggregationExtraQuestion | null;
   selectedSubQuestionOption: number | string | null;
+  joinedBeforeDate?: string;
 };
 
 const AggregationsDrawer: FC<Props> = ({
@@ -46,6 +42,7 @@ const AggregationsDrawer: FC<Props> = ({
   onFetchData,
   aggregationData,
   selectedSubQuestionOption,
+  joinedBeforeDate,
 }) => {
   const { user } = useAuth();
   const { actual_close_time, scaling, type, actual_resolve_time } =
@@ -54,7 +51,10 @@ const AggregationsDrawer: FC<Props> = ({
     () => getPostDrivenTime(actual_close_time),
     [actual_close_time]
   );
-  const tooltips = useMemo(() => generateAggregationTooltips(user), [user]);
+  const tooltips = useMemo(
+    () => generateAggregationTooltips(user, joinedBeforeDate),
+    [joinedBeforeDate, user]
+  );
   const [choiceItems, setChoiceItems] = useState(
     aggregationData
       ? generateChoiceItemsFromAggregations({
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/continuous_aggregations_chart.tsx b/front_end/src/app/(main)/aggregation-explorer/components/continuous_aggregations_chart.tsx
index 4d5ad23e48..22940967bd 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/continuous_aggregations_chart.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/continuous_aggregations_chart.tsx
@@ -21,10 +21,10 @@ import {
 import { cdfToPmf } from "@/utils/math";
 import { formatValueUnit } from "@/utils/questions/units";
 
-import { AggregationQuestionWithBots } from "../types";
+import { AggregationExtraQuestion } from "../types";
 
 type Props = {
-  questionData: AggregationQuestionWithBots;
+  questionData: AggregationExtraQuestion;
   activeAggregation: AggregateForecastHistory;
   selectedTimestamp: number | null;
 };
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/explorer.tsx b/front_end/src/app/(main)/aggregation-explorer/components/explorer.tsx
index 9fbbb1dcdc..5d20a5c6f7 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/explorer.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/explorer.tsx
@@ -26,7 +26,7 @@ import { logError } from "@/utils/core/errors";
 import { parseQuestionId } from "@/utils/questions/helpers";
 
 import { AggregationWrapper } from "./aggregation_wrapper";
-import { AggregationMethodWithBots } from "../types";
+import { AggregationExtraMethod } from "../types";
 
 function sanitizeUserIds(input: string): number[] {
   if (!input) return [];
@@ -59,7 +59,7 @@ const Explorer: FC<Props> = ({ searchParams }) => {
     string | number | null
   >(parseSubQuestionOption(question_id, option));
 
-  const [activeTab, setActiveTab] = useState<AggregationMethodWithBots | null>(
+  const [activeTab, setActiveTab] = useState<AggregationExtraMethod | null>(
     null
   );
   const [postInputText, setPostInputText] = useState<string>(
@@ -75,6 +75,11 @@ const Explorer: FC<Props> = ({ searchParams }) => {
       : searchParams.user_ids
     )?.toString() || ""
   );
+  const [joinedBeforeDate, setJoinedBeforeDate] = useState<string>(
+    (Array.isArray(searchParams.joined_before_date)
+      ? searchParams.joined_before_date[0]
+      : searchParams.joined_before_date) || ""
+  );
 
   // clear subquestion options when post id input changes
   useEffect(() => {
@@ -170,6 +175,10 @@ const Explorer: FC<Props> = ({ searchParams }) => {
       params.set("user_ids", cleanedIds.join(","));
     }
 
+    if (joinedBeforeDate.trim()) {
+      params.set("joined_before_date", joinedBeforeDate);
+    }
+
     router.push(`/aggregation-explorer?${params.toString()}`);
   };
 
@@ -213,6 +222,7 @@ const Explorer: FC<Props> = ({ searchParams }) => {
             onTabChange={setActiveTab}
             data={data}
             selectedSubQuestionOption={selectedSubQuestionOption}
+            joinedBeforeDate={joinedBeforeDate || undefined}
             additionalParams={{ userIds: sanitizeUserIds(userIdsText) }}
           />
         </>
@@ -291,7 +301,7 @@ const Explorer: FC<Props> = ({ searchParams }) => {
             value={selectedSubQuestionOption}
             onChange={handleSubQuestionSelectChange}
           />
-          {user?.is_staff && (
+          {
             // TODO: move "include bots" to here instead of in each tab
             // user ids should only be avilable to staff or whitelisted users
             // copy logic and parameters from the download data modal
@@ -299,26 +309,42 @@ const Explorer: FC<Props> = ({ searchParams }) => {
               <SectionToggle
                 title="Advanced options"
                 variant="light"
-                defaultOpen={!!userIdsText}
+                defaultOpen={!!userIdsText || !!joinedBeforeDate}
               >
                 <div className="space-y-3">
+                  {user?.is_staff && (
+                    <div>
+                      <label className="mb-1 block text-sm">
+                        User Ids (comma-separated integers). Will act as if
+                        these are the only participants.
+                      </label>
+                      <Input
+                        name="user_ids"
+                        type="text"
+                        value={userIdsText}
+                        onChange={(e) => setUserIdsText(e.target.value)}
+                        className="w-full cursor-default overflow-hidden rounded border border-gray-500 bg-white p-2 text-left text-sm leading-5 text-gray-900 focus:outline-none focus:ring-0 focus-visible:ring-2 focus-visible:ring-white focus-visible:ring-opacity-75 dark:bg-blue-950 dark:text-gray-200 sm:text-sm"
+                      />
+                    </div>
+                  )}
+
                   <div>
                     <label className="mb-1 block text-sm">
-                      User Ids (comma-separated integers). Will act as if these
-                      are the only participants.
+                      Filter for users who joined before date. Only effects
+                      Joined Before aggregation.
                     </label>
                     <Input
-                      name="user_ids"
-                      type="text"
-                      value={userIdsText}
-                      onChange={(e) => setUserIdsText(e.target.value)}
+                      name="joined_before_date"
+                      type="date"
+                      value={joinedBeforeDate}
+                      onChange={(e) => setJoinedBeforeDate(e.target.value)}
                       className="w-full cursor-default overflow-hidden rounded border border-gray-500 bg-white p-2 text-left text-sm leading-5 text-gray-900 focus:outline-none focus:ring-0 focus-visible:ring-2 focus-visible:ring-white focus-visible:ring-opacity-75 dark:bg-blue-950 dark:text-gray-200 sm:text-sm"
                     />
                   </div>
                 </div>
               </SectionToggle>
             </div>
-          )}
+          }
           <Button
             variant="primary"
             type="submit"
diff --git a/front_end/src/app/(main)/aggregation-explorer/components/histogram_drawer.tsx b/front_end/src/app/(main)/aggregation-explorer/components/histogram_drawer.tsx
index 469b8d93a8..62a30fc035 100644
--- a/front_end/src/app/(main)/aggregation-explorer/components/histogram_drawer.tsx
+++ b/front_end/src/app/(main)/aggregation-explorer/components/histogram_drawer.tsx
@@ -3,10 +3,10 @@ import { FC, memo } from "react";
 import Histogram from "@/components/charts/histogram";
 import { AggregateForecastHistory, QuestionType } from "@/types/question";
 
-import { AggregationQuestionWithBots } from "../types";
+import { AggregationExtraQuestion } from "../types";
 
 type Props = {
-  questionData: AggregationQuestionWithBots;
+  questionData: AggregationExtraQuestion;
   activeAggregation: AggregateForecastHistory;
   selectedTimestamp: number | null;
   aggregationIndex?: number;
diff --git a/front_end/src/app/(main)/aggregation-explorer/constants.ts b/front_end/src/app/(main)/aggregation-explorer/constants.ts
index 799eaec7b8..994c5df95e 100644
--- a/front_end/src/app/(main)/aggregation-explorer/constants.ts
+++ b/front_end/src/app/(main)/aggregation-explorer/constants.ts
@@ -1,53 +1,83 @@
 import { AggregationMethod } from "@/types/question";
 
-import { AggregationMethodWithBots, AggregationOption } from "./types";
+import { AggregationExtraMethod, AggregationOption } from "./types";
 
 export const AGGREGATION_EXPLORER_OPTIONS: readonly [
   AggregationOption,
   ...AggregationOption[],
 ] = [
   {
-    id: AggregationMethodWithBots.recency_weighted,
+    id: AggregationExtraMethod.recency_weighted,
     value: AggregationMethod.recency_weighted,
     label: "Recency-weighted median (no bots)",
     includeBots: false,
   },
   {
-    id: AggregationMethodWithBots.unweighted,
+    id: AggregationExtraMethod.unweighted,
     value: AggregationMethod.unweighted,
     label: "Unweighted median (no bots)",
     includeBots: false,
   },
   {
-    id: AggregationMethodWithBots.single_aggregation,
+    id: AggregationExtraMethod.single_aggregation,
     value: AggregationMethod.single_aggregation,
     label: "Single aggregation (no bots)",
     includeBots: false,
     isStaffOnly: true,
   },
   {
-    id: AggregationMethodWithBots.metaculus_prediction,
+    id: AggregationExtraMethod.metaculus_prediction,
     value: AggregationMethod.metaculus_prediction,
     label: "Metaculus prediction",
     includeBots: false,
   },
   {
-    id: AggregationMethodWithBots.recency_weighted_bot,
+    id: AggregationExtraMethod.recency_weighted_bot,
     value: AggregationMethod.recency_weighted,
     label: "Recency-weighted median (with bots)",
     includeBots: true,
   },
   {
-    id: AggregationMethodWithBots.unweighted_bot,
+    id: AggregationExtraMethod.unweighted_bot,
     value: AggregationMethod.unweighted,
     label: "Unweighted median (with bots)",
     includeBots: true,
   },
   {
-    id: AggregationMethodWithBots.single_aggregation_bot,
+    id: AggregationExtraMethod.single_aggregation_bot,
     value: AggregationMethod.single_aggregation,
     label: "Single aggregation (with bots)",
     includeBots: true,
     isStaffOnly: true,
   },
+  {
+    id: AggregationExtraMethod.metaculus_pros,
+    value: AggregationExtraMethod.metaculus_pros,
+    label: "Metaculus Pros",
+    includeBots: true,
+  },
+  {
+    id: AggregationExtraMethod.medalists,
+    value: AggregationExtraMethod.medalists,
+    label: "Medalists (all)",
+    includeBots: true,
+  },
+  {
+    id: AggregationExtraMethod.silver_medalists,
+    value: AggregationExtraMethod.silver_medalists,
+    label: "Medalists (silver or gold)",
+    includeBots: true,
+  },
+  {
+    id: AggregationExtraMethod.gold_medalists,
+    value: AggregationExtraMethod.gold_medalists,
+    label: "Medalists (gold)",
+    includeBots: true,
+  },
+  {
+    id: AggregationExtraMethod.joined_before_date,
+    value: AggregationExtraMethod.joined_before_date,
+    label: "Only Users Who Joined Before Date (set in Advanced options)",
+    includeBots: true,
+  },
 ];
diff --git a/front_end/src/app/(main)/aggregation-explorer/helpers.ts b/front_end/src/app/(main)/aggregation-explorer/helpers.ts
index fa82aabd5c..3066c46ede 100644
--- a/front_end/src/app/(main)/aggregation-explorer/helpers.ts
+++ b/front_end/src/app/(main)/aggregation-explorer/helpers.ts
@@ -2,55 +2,49 @@ import { uniq } from "lodash";
 
 import { METAC_COLORS, MULTIPLE_CHOICE_COLOR_SCALE } from "@/constants/colors";
 import { ChoiceItem } from "@/types/choices";
-import { Aggregations, QuestionType } from "@/types/question";
+import { QuestionType } from "@/types/question";
 import { CurrentUser } from "@/types/users";
 import { formatResolution } from "@/utils/formatters/resolution";
 
 import { AGGREGATION_EXPLORER_OPTIONS } from "./constants";
 import {
-  AggregationMethodWithBots,
-  AggregationQuestionWithBots,
+  AggregationExtraMethod,
+  AggregationExtraQuestion,
+  AggregationsExtra,
   AggregationTooltip,
 } from "./types";
 
 export function generateAggregationTooltips(
-  user: CurrentUser | null
+  user: CurrentUser | null,
+  joinedBeforeDate?: string
 ): AggregationTooltip[] {
-  const order: AggregationMethodWithBots[] = user?.is_superuser
-    ? [
-        AggregationMethodWithBots.recency_weighted,
-        AggregationMethodWithBots.unweighted,
-        AggregationMethodWithBots.single_aggregation,
-        AggregationMethodWithBots.recency_weighted_bot,
-        AggregationMethodWithBots.unweighted_bot,
-        AggregationMethodWithBots.single_aggregation_bot,
-        AggregationMethodWithBots.metaculus_prediction,
-      ]
-    : [
-        AggregationMethodWithBots.recency_weighted,
-        AggregationMethodWithBots.unweighted,
-        AggregationMethodWithBots.single_aggregation,
-        AggregationMethodWithBots.metaculus_prediction,
-        AggregationMethodWithBots.recency_weighted_bot,
-        AggregationMethodWithBots.unweighted_bot,
-        AggregationMethodWithBots.single_aggregation_bot,
-      ];
+  return AGGREGATION_EXPLORER_OPTIONS.filter((option) => {
+    if (option.isStaffOnly && (!user || !user.is_staff)) {
+      return false;
+    }
+    if (
+      option.id === AggregationExtraMethod.joined_before_date &&
+      !joinedBeforeDate
+    ) {
+      return false;
+    }
+    return true;
+  }).map((AggregationOption, index) => {
+    const baseLabel = AggregationOption.label;
+    const label =
+      AggregationOption.id === AggregationExtraMethod.joined_before_date &&
+      joinedBeforeDate
+        ? `Only Users who joined before ${joinedBeforeDate}`
+        : baseLabel;
 
-  return [...AGGREGATION_EXPLORER_OPTIONS]
-    .sort((a, b) => order.indexOf(a.id) - order.indexOf(b.id))
-    .map((AggregationOption, index) => {
-      if (AggregationOption.isStaffOnly && (!user || !user.is_staff)) {
-        return null;
-      }
-      return {
-        aggregationMethod: AggregationOption.value,
-        choice: AggregationOption.id,
-        label: AggregationOption.label,
-        includeBots: AggregationOption.includeBots,
-        color: MULTIPLE_CHOICE_COLOR_SCALE[index] ?? METAC_COLORS.gray["400"],
-      };
-    })
-    .filter((tooltip) => tooltip !== null) as AggregationTooltip[];
+    return {
+      aggregationMethod: AggregationOption.value,
+      choice: AggregationOption.id,
+      label,
+      includeBots: AggregationOption.includeBots,
+      color: MULTIPLE_CHOICE_COLOR_SCALE[index] ?? METAC_COLORS.gray["400"],
+    };
+  });
 }
 
 export function generateChoiceItemsFromAggregations({
@@ -59,14 +53,13 @@ export function generateChoiceItemsFromAggregations({
   tooltips,
   locale,
 }: {
-  question: AggregationQuestionWithBots;
+  question: AggregationExtraQuestion;
   selectedSubQuestionOption: number | string | null;
   tooltips: AggregationTooltip[];
   locale?: string;
 }): ChoiceItem[] {
   const choiceItems: ChoiceItem[] = [];
   const aggregations = question.aggregations;
-  const botAggregations = question.bot_aggregations;
   parseAggregationData({
     aggregations,
     choiceItems,
@@ -75,16 +68,6 @@ export function generateChoiceItemsFromAggregations({
     tooltips,
     selectedSubQuestionOption,
   });
-  botAggregations &&
-    parseAggregationData({
-      aggregations: botAggregations,
-      choiceItems,
-      question,
-      locale,
-      isBot: true,
-      tooltips,
-      selectedSubQuestionOption,
-    });
   return choiceItems;
 }
 
@@ -93,26 +76,20 @@ function parseAggregationData({
   choiceItems,
   question,
   locale,
-  isBot,
   tooltips,
   selectedSubQuestionOption,
 }: {
-  aggregations: Aggregations;
+  aggregations: AggregationsExtra;
   choiceItems: ChoiceItem[];
-  question: AggregationQuestionWithBots;
+  question: AggregationExtraQuestion;
   locale?: string;
   isBot?: boolean;
   tooltips: AggregationTooltip[];
   selectedSubQuestionOption: number | string | null;
 }) {
-  for (const key in aggregations) {
-    const aggregationKey = key as keyof Aggregations;
-    const aggregation = aggregations[aggregationKey];
-    const tooltip = tooltips.find(
-      (tooltip) =>
-        tooltip.aggregationMethod === aggregationKey &&
-        tooltip.includeBots === !!isBot
-    );
+  for (const [key, aggregation] of Object.entries(aggregations)) {
+    if (!aggregation) continue;
+    const tooltip = tooltips.find((tooltip) => tooltip.choice == key);
 
     if (!aggregation?.history) {
       continue;
diff --git a/front_end/src/app/(main)/aggregation-explorer/types.ts b/front_end/src/app/(main)/aggregation-explorer/types.ts
index de0336dbc8..bfe436c9a3 100644
--- a/front_end/src/app/(main)/aggregation-explorer/types.ts
+++ b/front_end/src/app/(main)/aggregation-explorer/types.ts
@@ -1,15 +1,20 @@
 import {
   AggregationQuestion,
   Aggregations,
-  AggregationMethod,
+  AggregateForecastHistory,
 } from "@/types/question";
 import { ThemeColor } from "@/types/theme";
 
-export type AggregationQuestionWithBots = AggregationQuestion & {
-  bot_aggregations?: Aggregations;
+// flexible version of Aggregations type which can include
+// arbitrarily named aggregations
+export type AggregationsExtra = Aggregations &
+  Partial<Record<string, AggregateForecastHistory>>;
+
+export type AggregationExtraQuestion = AggregationQuestion & {
+  aggregations: AggregationsExtra;
 };
 
-export enum AggregationMethodWithBots {
+export enum AggregationExtraMethod {
   recency_weighted = "recency_weighted",
   recency_weighted_bot = "recency_weighted_bot",
   unweighted = "unweighted",
@@ -18,19 +23,24 @@ export enum AggregationMethodWithBots {
   single_aggregation_bot = "single_aggregation_bot",
   metaculus_prediction = "metaculus_prediction",
   metaculus_prediction_bot = "metaculus_prediction_bot",
+  metaculus_pros = "metaculus_pros",
+  medalists = "medalists",
+  silver_medalists = "silver_medalists",
+  gold_medalists = "gold_medalists",
+  joined_before_date = "joined_before_date",
 }
 
 export type AggregationOption = {
-  id: AggregationMethodWithBots;
-  value: AggregationMethod;
+  id: AggregationExtraMethod;
+  value: string;
   label: string;
   includeBots: boolean;
   isStaffOnly?: boolean;
 };
 
 export type AggregationTooltip = {
-  aggregationMethod: AggregationMethod;
-  choice: AggregationMethodWithBots;
+  aggregationMethod: string;
+  choice: AggregationExtraMethod;
   label: string;
   includeBots: boolean;
   color: ThemeColor;
diff --git a/front_end/src/services/api/aggregation_explorer/aggregation_explorer.shared.ts b/front_end/src/services/api/aggregation_explorer/aggregation_explorer.shared.ts
index 7748f169a6..690083a39b 100644
--- a/front_end/src/services/api/aggregation_explorer/aggregation_explorer.shared.ts
+++ b/front_end/src/services/api/aggregation_explorer/aggregation_explorer.shared.ts
@@ -1,5 +1,5 @@
+import { AggregationExtraQuestion } from "@/app/(main)/aggregation-explorer/types";
 import { ApiService } from "@/services/api/api_service";
-import { AggregationQuestion } from "@/types/question";
 import { encodeQueryParams } from "@/utils/navigation";
 
 type AggregationExplorerParams = {
@@ -8,6 +8,7 @@ type AggregationExplorerParams = {
   includeBots?: boolean;
   aggregationMethods?: string;
   userIds?: number[];
+  joinedBeforeDate?: string;
 };
 
 class AggregationExplorerApi extends ApiService {
@@ -17,10 +18,11 @@ class AggregationExplorerApi extends ApiService {
       question_id: params.questionId?.toString() || "",
       include_bots: params.includeBots?.toString() || "false",
       aggregation_methods: params.aggregationMethods || "",
+      joined_before_date: params.joinedBeforeDate || "",
       ...(params.userIds !== undefined ? { user_ids: params.userIds } : {}),
     });
 
-    return await this.get<AggregationQuestion>(
+    return await this.get<AggregationExtraQuestion>(
       `/aggregation_explorer/${queryParams}`
     );
   }