LLM Evaluation: Assessing Large Language Models Using Their Peers
LLM Evaluation: Assessing Large Language Models Using Their Peers

The evolving practice of using LLMs to evaluate LLMs

In the rapidly evolving world of artificial intelligence, large language models (LLMs) have proven their potential in various applications, including translation, summarization, sentiment analysis, and more. With the increasing complexity and capabilities of these models, there is a growing need for effective evaluation techniques to assess their strengths and weaknesses.

Why is Evaluating Large Language Models Essential?

As LLMs continue to become more sophisticated and versatile, it is crucial to ensure their performance and safety. Assessing their capabilities and identifying potential biases or limitations helps improve their quality, making them more reliable for users. Moreover, evaluating LLMs helps developers identify areas for improvement, ultimately leading to better AI applications in various industries.

How to Evaluate LLMs Using Other LLMs

The process of evaluating LLMs using LLMs primarily involves generating test cases and evaluating the model’s performance on these cases. Typically, this includes:

  1. Automatic Test Generation: An LLM is used to create a diverse range of test cases, including different input types, contexts, and difficulty levels.
  2. Evaluation Metrics: The LLM being evaluated is tasked with solving the generated test cases. An LLM-based evaluation system then measures the model’s performance using predefined metrics, such as accuracy, fluency, and coherence.
  3. Comparison and Ranking: The results are compared to a baseline or other LLMs, offering insights into the relative strengths and weaknesses of the models.

What Are the Benefits of LLM-Based Evaluation?

Utilizing Large Language Models for evaluation offers several noteworthy benefits. One such advantage is scalability, as LLMs can automatically generate a vast number of test cases, enabling comprehensive evaluation without significant human intervention. This efficiency allows researchers to assess a model’s performance across various tasks and domains quickly.
Additionally, the flexibility of LLM-based evaluations makes it possible to tailor the evaluation process to different domains, applications, and specific use cases, ensuring relevance and applicability. The consistency of using a single LLM for generating test cases and evaluating the results also reduces the chances of human bias affecting the assessment. Lastly, continuous improvement is fostered through regular LLM-based evaluations, as developers can identify performance trends and track improvements over time, ensuring the ongoing advancement of AI technology.

How Does LLM-Based Evaluation Compare with Other Model Evaluation Techniques?

While LLM-based evaluation offers numerous benefits, it is important to view these benefits in context of broader techniques.

Human Evaluation

Human evaluation involves experts or crowdsourced workers assessing the output or performance of an LLM in a given context. This method provides qualitative feedback and can identify subtle nuances that LLM-based evaluation might miss.

Advantages Disadvantages
Ability to capture context-specific nuances and understandability.

Direct feedback on model performance from the target user group.

Time-consuming and expensive, especially for large-scale evaluations.

Inconsistencies due to subjective human opinions and biases.

Task-Specific Benchmarks

Task-specific benchmarks, such as GLUE or SuperGLUE, evaluate LLMs using a predefined set of tasks, with well-established metrics for each task. These benchmarks provide standardized, quantitative comparisons between different models.

Advantages Disadvantages
Consistent, reproducible evaluation using standardized tasks and metrics.

Allows for direct comparison of different LLMs on the same tasks.

Limited to the tasks and domains included in the benchmark, potentially missing other relevant use cases.

May not provide a comprehensive view of a model’s overall capabilities.

Intrinsic Metrics

Intrinsic metrics — such as ROUGE, BERT, and BLEU score — focus on measuring the similarity of a response to a provided reference answer. These metrics rely primarily on word or sentence-level similarity which capture syntax not semantic similarities.

Advantages Disadvantages
Can provide insights into the model’s behavior and “truthfulness.”

Useful for identifying specific areas of improvement.

Intrinsic metrics may not always correlate with real-world performance.

Focusing on a single metric may lead to over-optimization for that metric, neglecting other important aspects of performance.

In comparison to these methods, LLM-based evaluation offers scalability, flexibility, and consistency while reducing the impact of human bias. However, it is important to consider the limitations of LLM-based evaluation, such as ensuring diversity in test cases and addressing ethical concerns. In practice, combining different evaluation methods, including LLM-based evaluation, can provide a more comprehensive and holistic understanding of a model’s performance and capabilities.

What Are the Challenges and Ethical Considerations in LLM-Based Evaluation?

Despite the advantages of using LLMs for evaluation, it’s early days and there are challenges and considerations that must be addressed. Ensuring diversity in the evaluation process is critical, as it involves generating diverse and unbiased test cases that cover a wide range of possible scenarios. This diversity helps in identifying potential blind spots, biases, and limitations in the model being evaluated. Selecting appropriate evaluation metrics is another crucial aspect, as it directly impacts the accuracy and relevance of the assessment of an LLM’s performance. Researchers must carefully consider the metrics that best represent the desired outcomes and the model’s performance in specific tasks.

Ethical considerations also play a significant role when using LLMs for evaluation. The potential biases and limitations of LLMs should be acknowledged and addressed in the evaluation process to ensure fair and ethical use. As AI continues to permeate various aspects of society, it is essential to develop strategies to minimize the risks associated with biased or unfair AI systems. By incorporating ethical considerations into the LLM evaluation process, researchers can contribute to the development of more transparent, accountable, and responsible AI technology.

In addition to the above challenges, a comparison done by Microsoft Research showed that the justification process used by LLMs when evaluating generated responses does not necessarily mirror that of a human. There are some assumptions that were made by the LLM, for example, downweighting shorter answers, that human evaluators did not use when evaluating responses. To overcome these shortcomings, we must ensure that models are calibrated like humans for evaluation by creating nuanced and information instructions to the model through thoughtful prompt engineering.

How Do OpenAI Evals Help With Model Evaluation?

OpenAI has launched an open-source software framework, known as Evals, to evaluate the performance of its AI models in tandem with GPT-4. OpenAI Evals provides developers with tools to generate prompts using datasets, measure the quality of completions by the LLMs, and compare performance across different datasets and models. The framework also includes templates that have proven useful in evaluating OpenAI’s own models, which users can leverage to evaluate their own systems built on OpenAI models. With Evals, developers can evaluate their LLM applications without writing any code at all. However, for those who wish to tailor the evaluation process to their specific needs, custom Evals can also be written and added.

Evals is designed not only to enable individuals to assess their own applications, but also to provide a vehicle for sharing and crowdsourcing benchmarks for OpenAI’s LLMs; Evals will help identify deficiencies and provide feedback to direct future enhancements. OpenAI actively reviews Evals when considering improvements for models under development, allowing users to contribute to the improvement of OpenAI’s products while improving their own applications.


Evaluating LLMs with LLMs is a promising approach to assess the performance and capabilities of these powerful AI models. This self-reflective technique provides scalability, flexibility, and consistency, enabling developers to identify areas of improvement and ensure the continued advancement of AI technology. However, it is essential to consider the challenges and ethical implications associated with this method to ensure a comprehensive and fair evaluation process.