New Research Reveals Limitations of Large Language Models in Multi-Turn Conversations

A recent study from Microsoft Research and Salesforce highlights a critical limitation in even the most advanced Large Language Models (LLMs): their performance significantly deteriorates when instructions are given in stages rather than all at once. The research found an average performance drop of 39% across six tasks when prompts are split over multiple turns:

The study reveals that the reliability of responses drastically declines with stage-based instructions. Noteworthy models like ChatGPT-4.1 and Gemini 2.5 Pro exhibit fluctuations between near-perfect answers and significant failures depending on the phrasing of tasks, with output consistency dropping by over 50%.

Understanding the Problem: The Sharding Method

The paper presents a novel approach termed sharding, which divides comprehensive prompts into smaller fragments, presenting them one at a time throughout the conversation.

This methodology can be likened to placing a complete order at a restaurant versus engaging in a collaborative dialogue with the waiter:

Key Findings and Recommendations

The research indicates that LLMs tend to generate excessively long responses, clinging to misconceived insights even after their inaccuracies are evident. This behavior can lead the system to completely lose track of the conversation.

Interestingly, it has been noted, as many users have experienced, that starting a new conversation often proves to be a more effective strategy than continuing an ongoing one.

‘If a conversation with an LLM did not yield expected outcomes, collecting the same information in a new conversation can lead to vastly improved results.’

Agent Frameworks: A Double-Edged Sword

While systems like Autogen or LangChain may enhance outcomes by acting as intermediary layers between users and LLMs, the authors argue that such abstractions should not be necessary. They propose:

‘Multi-turn capabilities could be integrated directly into LLMs instead of relegated to external frameworks.’

Sharded Conversations: Experimental Setup

The study introduces the idea of breaking traditional single-turn instructions into smaller, context-driven shards. This new construct simulates dynamic, exploratory engagement patterns similar to those found in systems like ChatGPT or Google Gemini.

The simulation progresses through three entities: the assistant, the evaluated model; the user, who reveals shards; and the system, which monitors and rates the interaction. This configuration mimics real-world dialogue by allowing flexibility in how the conversation unfolds.

Insightful Simulation Scenarios

The researchers employed five distinct simulations to scrutinize model behavior under various conditions:

• Full: The model receives the entire instruction in a single turn.
• Sharded: The instruction is divided and provided across multiple turns.
• Concat: Shards are consolidated into a list, removing their conversational structure.
• Recap: All previous shards are reiterated at the end for context before a final answer.
• Snowball: Every turn restates all prior shards for increased context visibility.

Evaluation: Tasks and Metrics

Six generation tasks were employed, including code generation and Text-to-SQL prompts from established datasets. Performance was gauged using three metrics: average performance, aptitude, and unreliability.

Contenders and Results

Fifteen models were evaluated, revealing that all showed performance degradation in simulated multi-turn settings, coining this phenomenon as Lost in Conversation. The study emphasizes that higher performance models struggled similarly, dispelling the assumption that superior models would maintain better reliability.

Conclusions and Implications

The findings underscore that exceptional single-turn performance does not equate to multi-turn reliability. This raises concerns about the real-world readiness of LLMs, urging caution against dependency on simplified benchmarks that overlook the complexities of fragmented interactions.

The authors conclude with a call to treat multi-turn ability as a fundamental skill of LLMs—one that should be prioritized instead of externalized into frameworks:

‘The degradation observed in experiments is a probable underestimation of LLM unreliability in practical applications.’