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Can Large Language Models Help Research Causality?

Exploring the potential of LLMs in identifying cause-and-effect relationships.

Nick Huntington-Klein, Eleanor J. Murray

― 5 min read


LLMs and Causality: A LLMs and Causality: A Mixed Bag complex cause-and-effect. Assessing LLMs' role in understanding
Table of Contents

Large Language Models (LLMs) are tools that can generate human-like text. They can write stories, answer questions, and even create songs. But can they help Researchers understand cause-and-effect relationships? This is a hot topic right now, and we're going to explore it.

What are Large Language Models?

LLMs are computer programs trained on a lot of text. They learn patterns in language and can predict what words should come next. Think of it as a really smart parrot that has read the entire internet. While parrots might not help with complex math, LLMs can be useful in fields like medicine, science, and even creative writing.

The Quest for Causal Knowledge

Causality is about understanding how one thing affects another. For example, if you eat too much chocolate, you might get a tummy ache. Researchers want to know these relationships, especially when looking at health data, to make better decisions and recommendations.

However, figuring out these cause-and-effect links can be tricky. Data collected from real life can be messy, and many factors can confuse the results. That's where LLMs come in—they might help researchers identify these connections without spending years sifting through data.

The Coronary Drug Project: A Case Study

Let's dive into a specific example called the Coronary Drug Project (CDP). This was a large study conducted between 1965 and 1985 to find ways to reduce heart-related deaths in men. It involved a group of participants who received either a drug or a placebo (that's just a fancy term for a sugar pill with no medicine).

What is a Confounder?

In studies like the CDP, researchers talk about "Confounders." These are Variables that can cloud the results. For example, if you want to know if a new heart drug works, but people's ages and lifestyles vary widely, those factors might confuse the results. A confounder can lead to incorrect conclusions if not handled correctly.

What Did Researchers Find?

In the CDP, researchers thought that confounding was a big problem. They found that even after adjusting for certain variables, a significant difference in death rates remained. But later analyses using better methods brought this difference down. This shows that as methods improve, understanding of complex relationships can also improve.

Can LLMs Help?

Now, the big question: can LLMs help identify confounders? Researchers conducted tests to see if these models could provide accurate suggestions about what factors should be considered when analyzing the CDP data.

The Experiment

Researchers used different LLMs to designate variables as confounders. They presented a set of variables, some known to be confounders and some not, to see how well LLMs could identify them. The study aimed to see if LLMs could repeat expert knowledge without being explicitly told the answers.

The Results

Results were mixed. LLMs were pretty good at identifying some confounders, especially those widely accepted in expert literature. However, they also tended to label some variables incorrectly as confounders, which raised eyebrows.

Why LLMs Struggled

There are several reasons LLMs struggled with this task:

  1. Lack of True Understanding: LLMs don't truly understand causality; they just mimic patterns they learned during training. They know how to string words together based on what they've seen, not based on real-world relationships.

  2. Data Limitations: While LLMs have access to a lot of information, they might not have everything they need to provide accurate answers. If a relevant study is missing from their training data, their output might not be reliable.

  3. Inconsistency: The models sometimes gave different answers for the same questions based on small changes in prompt design. It's as if you asked your friend about a movie twice, and they gave two completely different reviews.

Example Findings

In the study, one LLM had a tendency to label around 90% of certain variables as confounders. While this sounds impressive, it also included many variables that experts would not consider confounders. This over-eagerness to label could lead to confusion in real research settings.

The Role of Prompts

The way researchers ask questions, or "prompt" the LLMs, makes a big difference. There were two main methods used in the study:

  1. Direct Prompts: Asking the model directly if a variable is a confounder.
  2. Indirect Prompts: Asking about the relationship between a variable and the outcome separately.

Both methods yielded different results. The indirect approach sometimes resulted in higher rates of confounder designations, possibly because it forced the LLMs to consider multiple relationships more broadly.

Conclusion: A Work in Progress

So, can LLMs act as reliable helpers in understanding causal relationships? It seems they have potential, but they’re not quite there yet. They can assist in flagging potential confounders, but the results aren't consistent or reliable enough to replace expert knowledge.

In short, LLMs might be more like quirky sidekicks than main characters in the detective story of causal inference. They'll help you look under the couch for clues, but you might still want to do the heavy lifting yourself when it comes to research.

As technology continues to advance, we may see LLMs improve in their causal reasoning abilities. Who knows? They might just surprise us by turning into the Sherlock Holmes of the scientific world, helping us piece together the complexities of causality with even better accuracy and consistency.

Final Thoughts

The relationship between LLMs and causal knowledge is still unfolding. For now, they remain intriguing tools in the toolbox of researchers, but like all tools, they work best with a knowledgeable human hand guiding them. So, while these models can generate eye-catching text and offer some insights, it's essential to remember that they cannot replace human thinking and expertise.

Original Source

Title: Do LLMs Act as Repositories of Causal Knowledge?

Abstract: Large language models (LLMs) offer the potential to automate a large number of tasks that previously have not been possible to automate, including some in science. There is considerable interest in whether LLMs can automate the process of causal inference by providing the information about causal links necessary to build a structural model. We use the case of confounding in the Coronary Drug Project (CDP), for which there are several studies listing expert-selected confounders that can serve as a ground truth. LLMs exhibit mediocre performance in identifying confounders in this setting, even though text about the ground truth is in their training data. Variables that experts identify as confounders are only slightly more likely to be labeled as confounders by LLMs compared to variables that experts consider non-confounders. Further, LLM judgment on confounder status is highly inconsistent across models, prompts, and irrelevant concerns like multiple-choice option ordering. LLMs do not yet have the ability to automate the reporting of causal links.

Authors: Nick Huntington-Klein, Eleanor J. Murray

Last Update: Dec 13, 2024

Language: English

Source URL: https://arxiv.org/abs/2412.10635

Source PDF: https://arxiv.org/pdf/2412.10635

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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