International finance institutions provide substantial support for capacity building, knowledge transfer, and technical assistance, with advisory services becoming an increasingly important part of their work. Recently, the World Bank, IFC, and the Multilateral Investment Guarantee Agency have taken steps to integrate their knowledge work under one unified framework, the Bank Group Knowledge Bank, reflecting the increasing significance of knowledge in the Bank Group’s development work. As the Bank Group deepens its role as a Knowledge Bank, understanding whether, how, and under what circumstances knowledge-based activities produce results and impacts becomes increasingly critical. This, in turn, requires being able to systematically evaluate knowledge interventions—a task made difficult by the often intangible or hard-to-measure outcomes that these interventions pursue.

This paper has reflected on the methodological challenges of evaluating advisory services projects. It draws on more than 15 years of organizational learning from IFC’s structured self-evaluation approach and IEG’s subsequent validation of advisory services effectiveness to highlight the evidence standards that must be met in the validation process, and the methodological solutions and approaches that have enabled IEG to systematically validate these projects. While these challenges may not be entirely overcome, their effects can be mitigated and divergences in interpretation minimized through several analytical strategies that support inference about these hard-to-measure outcomes. This includes strengthening evidence collection and triangulation, conducting field-based evaluations for deeper impact analysis, refining project objectives and theories of change, and leveraging Country Program Evaluations and thematic studies to address longer-term and broader effects. Engaging independent reviewers with sector-specific expertise and clearly distinguishing between project and team performance further enhance the credibility and robustness of evaluations.

In many respects, these strategies parallel and embed principles fundamental to theory-based case-based approaches, such as process tracing, which are recognized as having a comparative advantage in their “ability to assess interventions that do not lend themselves to quantification or experimentation” (Beach and Raimondo 2025, 33), including knowledge work. Process tracing and other theory-based evaluation approaches, such as contribution analysis, typically rely on more intensive primary data collection than is possible within the self-evaluation and validation process. Nevertheless, the approach described in this paper allows leveraging key theory-based evaluation principles like some primary data collection guided by reconstructed theories of change, trying to capture the fingerprints left by an intervention on observed change process, and weighting the strength of evidence. This allows IEG to put forth a systematic approach that can provide evidence to causally link interventions and outcomes, and speak to the mechanisms underlying these processes, within the constraints of what is primarily a desk-based exercise.

Even when outcomes are intangible and difficult to measure directly, a key takeaway from IEG’s experience is that evaluators can meaningfully go beyond assessing project ratings to generate insights into the drivers of success or failure, work quality challenges, and lessons learned. These insights inform the design and implementation of future interventions, enhance internal management reporting, and contribute to thematic and corporate evaluations. Ultimately, the goal is to foster organizational learning and continuous improvement.

Another key takeaway from IEG’s practice is that, while establishing a comprehensive evaluation framework is necessary, the undertaking of institutional arrangements to build an evaluation system around it and close collaboration between Operations and Independent Evaluation to maintain and update the framework and system are equally critical. Embedding self-evaluation as a core component of the project’s operational cycle ensures that assessment is not an afterthought but an integral part of operational culture. A robust evaluation system is underpinned by clear policies, guidelines, training, information technology platforms, and dedicated resources. Evaluation extends beyond a single report, encompassing a suite of practices and governance structures, including oversight by a central unit and support from management and monitoring and evaluation officers. Sustained collaboration between operational teams and independent evaluators is essential for credibility and adaptability. This partnership enables the system to evolve in response to changes in advisory services, with regular updates to methodologies.

By implementing these measures, organizations can build a more effective, transparent, and adaptive evaluation system for advisory services, ultimately driving better outcomes and organizational learning.