Despite mature backtesting frameworks, Intercom repeatedly sees promising offline results fail in production. The "messiness of real human interaction" is unpredictable, making at-scale A/B tests essential for validating AI performance improvements, even for changes as small as a tenth of a percentage point.

Related Insights

Don't treat evals as a mere checklist. Instead, use them as a creative tool to discover opportunities. A well-designed eval can reveal that a product is underperforming for a specific user segment, pointing directly to areas for high-impact improvement that a simple "vibe check" would miss.

To ensure AI reliability, Salesforce builds environments that mimic enterprise CRM workflows, not game worlds. They use synthetic data and introduce corner cases like background noise, accents, or conflicting user requests to find and fix agent failure points before deployment, closing the "reality gap."

The vast majority of Intercom Fin's resolution rate increase came from optimizing retrieval, re-ranking, and prompting. GPT-4 was already intelligent enough for the task; the real gains were unlocked by improving the surrounding architecture, not waiting for better foundation models.

AI agents can continuously experiment with variables like subject lines, send times, and offers for each individual user. This level of granular, ongoing A/B testing is impossible to manage manually, unlocking significant performance lifts that compound over time.

To ensure product quality, Fixer pitted its AI against 10 of its own human executive assistants on the same tasks. They refused to launch features until the AI could consistently outperform the humans on accuracy, using their service business as a direct training and validation engine.

The common mistake in building AI evals is jumping straight to writing automated tests. The correct first step is a manual process called "error analysis" or "open coding," where a product expert reviews real user interaction logs to understand what's actually going wrong. This grounds your entire evaluation process in reality.

Do not blindly trust an LLM's evaluation scores. The biggest mistake is showing stakeholders metrics that don't match their perception of product quality. To build trust, first hand-label a sample of data with binary outcomes (good/bad), then compare the LLM judge's scores against these human labels to ensure agreement before deploying the eval.

Developers often test AI systems with well-formed, correctly spelled questions. However, real users submit vague, typo-ridden, and ambiguous prompts. Directly analyzing these raw logs is the most crucial first step to understanding how your product fails in the real world and where to focus quality improvements.

Open and click rates are ineffective for measuring AI-driven, two-way conversations. Instead, leaders should adopt new KPIs: outcome metrics (e.g., meetings booked), conversational quality (tracking an agent's 'I don't know' rate to measure trust), and, ultimately, customer lifetime value.

To set realistic success metrics for new AI tools, Descript used its most popular pre-AI feature, "remove filler words," as the baseline. They compared adoption and retention of new AI features against this known winner, providing a clear, internal benchmark for what "good" looks like instead of guessing at targets.

Intercom Finds Offline Evals Unreliable; Large-Scale A/B Tests Are the Only True Test | RiffOn