diff --git a/src/client/base.ts b/src/client/base.ts
index 4104da7..ab6f322 100644
--- a/src/client/base.ts
+++ b/src/client/base.ts
@@ -4,7 +4,7 @@ import https from "node:https";
 import { dirname, join } from "node:path";
 import { fileURLToPath } from "node:url";
 
-import axios, { AxiosInstance } from "axios";
+import axios, { AxiosInstance, AxiosResponse } from "axios";
 import { parse as csvParse } from "csv-parse/sync";
 import { z } from "zod";
 
@@ -153,24 +153,28 @@ export class BaseIterableClient {
 
   /**
    * Parse CSV response into an array of objects using csv-parse library
+   * @throws IterableResponseValidationError if CSV parsing fails
    */
-  public parseCsv(data: string): any[] {
-    if (!data) {
+  public parseCsv(response: AxiosResponse<string>): Record<string, string>[] {
+    if (!response.data) {
       return [];
     }
 
     try {
-      return csvParse(data, {
+      return csvParse(response.data, {
         columns: true, // Use first line as headers
         skip_empty_lines: true,
         trim: true,
       });
     } catch (error) {
-      // Log error but don't throw - return empty array for graceful degradation
-      logger.warn("Failed to parse CSV data", {
-        error: error instanceof Error ? error.message : String(error),
-      });
-      return [];
+      // Throw validation error to maintain consistent error handling
+      // This allows callers to handle parse failures appropriately
+      throw new IterableResponseValidationError(
+        200,
+        response.data,
+        `CSV parse error: ${error instanceof Error ? error.message : String(error)}`,
+        response.config?.url
+      );
     }
   }
 
diff --git a/src/client/campaigns.ts b/src/client/campaigns.ts
index a9c9119..960edab 100644
--- a/src/client/campaigns.ts
+++ b/src/client/campaigns.ts
@@ -4,6 +4,7 @@ import {
   ArchiveCampaignsParams,
   ArchiveCampaignsResponse,
   ArchiveCampaignsResponseSchema,
+  CampaignMetricsResponse,
   CancelCampaignParams,
   CreateCampaignParams,
   CreateCampaignResponse,
@@ -111,7 +112,7 @@ export function Campaigns<T extends Constructor<BaseIterableClient>>(Base: T) {
 
     async getCampaignMetrics(
       options: GetCampaignMetricsParams
-    ): Promise<any[]> {
+    ): Promise<CampaignMetricsResponse> {
       const params = new URLSearchParams();
       params.append("campaignId", options.campaignId.toString());
       if (options.startDateTime)
@@ -127,7 +128,7 @@ export function Campaigns<T extends Constructor<BaseIterableClient>>(Base: T) {
       );
 
       // Parse CSV response into array of objects
-      return this.parseCsv(response.data);
+      return this.parseCsv(response);
     }
 
     async scheduleCampaign(
diff --git a/src/client/experiments.ts b/src/client/experiments.ts
index d5e1412..8972bc7 100644
--- a/src/client/experiments.ts
+++ b/src/client/experiments.ts
@@ -42,7 +42,7 @@ export function Experiments<T extends Constructor<BaseIterableClient>>(
       });
 
       // Parse CSV response into array of objects
-      return this.parseCsv(response.data);
+      return this.parseCsv(response);
     }
   };
 }
diff --git a/src/types/campaigns.ts b/src/types/campaigns.ts
index a09a900..581b94e 100644
--- a/src/types/campaigns.ts
+++ b/src/types/campaigns.ts
@@ -114,6 +114,9 @@ export type GetCampaignResponse = z.infer<typeof GetCampaignResponseSchema>;
 export type GetCampaignMetricsParams = z.infer<
   typeof GetCampaignMetricsParamsSchema
 >;
+export type CampaignMetricsResponse = z.infer<
+  typeof CampaignMetricsResponseSchema
+>;
 export type CreateCampaignParams = z.infer<typeof CreateCampaignParamsSchema>;
 export type CreateCampaignResponse = z.infer<
   typeof CreateCampaignResponseSchema
@@ -136,8 +139,10 @@ export const CampaignsResponseSchema = z.object({
   campaigns: z.array(CampaignDetailsSchema),
 });
 
+// The API returns CSV data which we parse into objects
+// All CSV values are strings
 export const CampaignMetricsResponseSchema = z
-  .array(z.record(z.string(), z.any()))
+  .array(z.record(z.string(), z.string()))
   .describe("Parsed campaign metrics data");
 
 // Campaign creation schemas
diff --git a/src/types/experiments.ts b/src/types/experiments.ts
index 6d62f00..074bcfe 100644
--- a/src/types/experiments.ts
+++ b/src/types/experiments.ts
@@ -8,7 +8,7 @@ import { IterableDateTimeSchema } from "./common.js";
 
 // The API returns CSV data which we parse into objects
 export const ExperimentMetricsResponseSchema = z
-  .array(z.record(z.string(), z.any()))
+  .array(z.record(z.string(), z.string()))
   .describe("Parsed experiment metrics data");
 
 export const GetExperimentMetricsParamsSchema = z
diff --git a/tests/unit/campaigns.test.ts b/tests/unit/campaigns.test.ts
index d976005..d172979 100644
--- a/tests/unit/campaigns.test.ts
+++ b/tests/unit/campaigns.test.ts
@@ -288,6 +288,15 @@ describe("Campaign Management", () => {
         { responseType: "text" }
       );
     });
+
+    it("should throw IterableResponseValidationError for invalid CSV", async () => {
+      const mockResponse = { data: "invalid,csv\n\ndata" };
+      mockAxiosInstance.get.mockResolvedValue(mockResponse);
+
+      await expect(
+        client.getCampaignMetrics({ campaignId: 12345 })
+      ).rejects.toThrow("CSV parse error");
+    });
   });
 
   describe("getChildCampaigns", () => {
diff --git a/tests/unit/experiments.test.ts b/tests/unit/experiments.test.ts
index 101aa33..fa73c19 100644
--- a/tests/unit/experiments.test.ts
+++ b/tests/unit/experiments.test.ts
@@ -217,5 +217,14 @@ describe("Experiment Operations", () => {
       expect(result).toEqual(expectedParsedData);
       expect(Array.isArray(result)).toBe(true);
     });
+
+    it("should throw IterableResponseValidationError for invalid CSV", async () => {
+      const mockResponse = { data: "invalid,csv\n\ndata" };
+      mockAxiosInstance.get.mockResolvedValue(mockResponse);
+
+      await expect(client.getExperimentMetrics()).rejects.toThrow(
+        "CSV parse error"
+      );
+    });
   });
 });