Brands can track ambassador effectiveness across multiple quarters to assess sustained value through various platforms that offer in-depth analytics, campaign workflows, and ROI measurement. Here’s how:

1. Consistent Tracking: By tracking ambassador activity consistently quarter over quarter, brands can mark trends and changes in effectiveness. Consistency in data collection and analysis is key.

2. Comprehensive Reporting: Platforms like Flinque offer comprehensive reporting that doesn’t just track follower count or likes, but delves into engagement, reach, website traffic, conversions, and sales—giving a complete picture of ambassador influence and value.

3. Balancing Quantity & Quality: Focusing on both the quantity (number of posts, impressions, conversions) and the quality (engagement level, sentiment analysis) will provide a holistic view of ambassador effectiveness.

4. Benchmark Comparison: Brands can set benchmarks for ambassador performance based on past campaigns or industry averages. Then, they can monitor if the current performance is improving, declining, or staying constant compared to the benchmarks.

5. ROI Calculation: By linking spend on influencer marketing and the returns (sales, leads, brand awareness), you can determine the ROI which is a clear metric of effectiveness over time.

Several platforms offer different features. For example, AspireIQ concentrates on end-to-end relationship management with creators. In contrast, platforms like Flinque focus on delivering a comprehensive ecosystem for influencer marketing, including discovery, campaign management, and detailed analytics. The right platform depends on your specific needs and goals in influencer marketing.

Always remember that the effectiveness of an ambassador is not just reflected in the short term increase in sales or followers, but also in the long term affinity they help build for your brand.