Large institutions are systematically less capable than small ones at retaining the knowledge of why things are the way they are.
Why Scale Erodes Memory
Institutional memory — the retained knowledge of what the institution has tried, what has worked, what has failed, and why the current arrangements exist in their current form — decays faster in large institutions than in small ones, not because large institutions care less about retaining this knowledge but because the structural features of scale make retention harder. In a small institution, the people who made the decisions are often still present; the knowledge of the reasoning behind those decisions is carried in their memory and transmitted through the relationships they maintain with colleagues who were present at the time. In a large institution, the people who made the decisions have often moved on before the decisions' implications become visible; the reasoning behind those decisions lives in documents that may or may not have been written, in relationships that may or may not be maintained, and in institutional stories that may or may not be accurately transmitted.
The Specific Knowledge That Decays First
Institutional memory loss is not random — it preferentially affects the knowledge types that are most valuable and hardest to retain. Negative knowledge — the knowledge of what the institution tried that did not work, and why — decays faster than positive knowledge. The decision to avoid a specific approach was made because of an analysis of why that approach fails in this context; when the people who conducted the analysis are gone, the avoidance may continue as an unexplained institutional norm, or it may be reversed by new people who are not aware of the prior analysis and reinvent the approach with the expectation that it will succeed.
Tacit knowledge — the knowledge of how to do things effectively that exists in the practice of experienced people rather than in documentation — decays completely when the practitioners depart. A complex operational process that relies on the judgment of experienced practitioners to navigate correctly becomes a formal procedure that is executed according to documentation rather than judgment, with a corresponding reduction in the quality of outcomes in the cases where judgment would have produced different results than the formal procedure.
Large institutions remember what they wrote down and forget what they only knew. The institutional memory that matters most — the knowledge of why things are the way they are, and what happens when you do what the institution has already tried — lives in the people who were there, not in the documentation. When those people leave, the knowledge leaves with them.
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