Evaluating Ranking Changes in Live Professional Legal Search Systems: Challenges and Limitations of Common Approaches

Conceitos Básicos

Common ranking evaluation methods, including test collections, user surveys, and A/B testing, are suboptimal for evaluating changes to ranking algorithms in live professional legal search systems due to characteristics of the legal domain, such as high recall requirements, limited user data, and commercial constraints.

Resumo

The paper discusses the challenges of applying common ranking evaluation methods to live professional legal search systems, using data from a legal search engine as an example.
Key highlights:

Legal information retrieval (IR) has distinct characteristics that make it different from web search, such as high recall requirements, time pressure for users, and limited user data due to specialized jurisdictions.
Test collections based on expert relevance judgments are expensive to create and maintain, and do not capture the dynamic nature of legal search results.
Implicit feedback data is too sparse, as queries are often unique to individual users, limiting the ability to create test collections.
User surveys, including ranking preference surveys and Net Promoter Score, provide inconclusive results due to the small number of respondents and the adaptability of user search strategies.
A/B testing is not feasible in the legal domain due to commercial constraints around providing different results to users.
The authors conclude that common evaluation methods are suboptimal for evaluating ranking changes in live professional legal search systems, and suggest exploring less common approaches, such as cost-based evaluation models, in future work.

Estatísticas

"Legal professionals spend approximately 15 hours in a week seeking case law [18]."
"Of all queries investigated, 25% is inferred, or assumed known-item search and 75% are other searches [38]."
"The majority of queries is unique to one user [38]."
"On average 2.4 documents in the top-10 remained in the same position, whilst 7.6 documents changed position. Of these 7.6 documents 1.4 documents moved up, 2.9 moved down, and 3.2 were replaced [survey data]."
"The nDCG@20 was 2.08 for the old ranking, and 1.96 for the new ranking [survey data]."

Citações

"Simply put, it is in a legal dispute first of all important to know more than the opposing lawyer(s) and not to fulfill abstract ideals of completeness" [15].
"Explaining the predominance of Boolean search in, e.g., prior art search and systematic review" [39].

Principais Insights Extraídos De

High Recall, Small Data

by Gineke Wigge... às arxiv.org 03-29-2024

https://arxiv.org/pdf/2403.18962.pdf

Perguntas Mais Profundas

How can cost-based evaluation models be applied to assess the effectiveness of ranking changes in live professional legal search systems?

Cost-based evaluation models can be applied to assess the effectiveness of ranking changes in live professional legal search systems by considering the costs associated with the changes made to the system. These models take into account the resources expended in implementing the changes, such as development time, testing, and potential impact on user experience. By analyzing the costs incurred in making the ranking changes and comparing them to the benefits or improvements observed in the system's performance, a cost-based evaluation can provide insights into the efficiency and effectiveness of the changes.
In the context of legal search systems, cost-based evaluation models can help decision-makers understand the return on investment of implementing ranking changes. This approach involves quantifying the costs associated with the development and deployment of the new ranking algorithm, including any adjustments made based on user feedback or system performance metrics. By comparing these costs to the improvements in search results quality, user satisfaction, or other relevant metrics, stakeholders can make informed decisions about the value of the ranking changes.

What alternative evaluation methods, beyond those discussed in this paper, could be suitable for evaluating ranking changes in live professional search systems with limited user data?

In addition to the evaluation methods discussed in the paper, several alternative approaches could be suitable for evaluating ranking changes in live professional search systems with limited user data:

Behavioral Analysis: Conducting in-depth analysis of user behavior patterns, such as click-through rates, dwell time on search results, and query reformulation, can provide valuable insights into the effectiveness of ranking changes. By tracking and analyzing user interactions with the search system, stakeholders can assess the impact of the changes on user engagement and satisfaction.

Expert Review Panels: Establishing expert review panels comprising legal professionals, domain experts, and system developers can offer qualitative assessments of ranking changes. These panels can evaluate the relevance and quality of search results, providing valuable feedback on the effectiveness of the new ranking algorithm.

Longitudinal Studies: Implementing longitudinal studies to track changes in user behavior and system performance over time can help evaluate the long-term impact of ranking changes. By collecting data at regular intervals post-implementation, stakeholders can assess the sustainability and effectiveness of the changes.

User Feedback Surveys: Implementing targeted user feedback surveys to gather qualitative insights on user satisfaction, preferences, and perceived improvements can complement quantitative evaluation methods. By directly engaging users and soliciting their feedback, stakeholders can gain a deeper understanding of the user experience and the impact of ranking changes.

How can the legal search community collaborate with users to develop more effective evaluation approaches that balance the needs of legal professionals and the constraints of commercial systems?

Collaboration between the legal search community and users is essential to develop more effective evaluation approaches that balance the needs of legal professionals and the constraints of commercial systems. Here are some strategies for fostering collaboration:

User Involvement: Engage legal professionals in the evaluation process by soliciting their feedback, preferences, and suggestions for improving the search system. By involving users in the design and evaluation of ranking changes, stakeholders can ensure that the system meets the specific needs and expectations of the legal community.

User Testing: Conduct user testing sessions where legal professionals interact with the search system and provide real-time feedback on the usability, relevance, and effectiveness of the ranking algorithm. By observing user behavior and collecting direct feedback, stakeholders can identify areas for improvement and validate the impact of ranking changes.

Feedback Mechanisms: Implement feedback mechanisms within the search system that allow users to submit comments, suggestions, and ratings on search results. By creating channels for continuous feedback, stakeholders can gather insights from users on an ongoing basis and iteratively improve the system based on user input.

Collaborative Workshops: Organize collaborative workshops or focus groups where legal professionals, system developers, and researchers come together to discuss evaluation methods, challenges, and opportunities for enhancing the search system. By fostering open dialogue and collaboration, stakeholders can co-create evaluation approaches that address the unique needs and constraints of the legal search community.

By fostering a culture of collaboration, transparency, and user-centered design, the legal search community can develop evaluation approaches that prioritize user needs, enhance system performance, and drive continuous improvement in professional search systems.