By Vaibhav Verma
Your infrastructure is managed by one engineer. Your payment system is understood by one architect. Your notification system is maintained by whoever built it three years ago.
These aren't strengths. They're catastrophic risks.
Knowledge silos — when critical information is concentrated in one or two people — destroy team productivity, reliability, and resilience.
The Hidden Costs
Bus Factor Drops to One
Your "bus factor" is how many people can leave before the team fails. Healthy teams have bus factor 3+. You lose one person, the team adjusts.
Teams with knowledge silos have bus factor 1. That person knows something critical. They leave or get hit by a bus (hence the name). Now you're in crisis.
Your database architect is the only one who understands your data model. They leave. Now you can't:
Add new tables without consulting them. Optimize queries (nobody knows why they're designed that way). Scale the database (only they understand constraints). Onboard engineers in the data layer (nobody can teach them).
You're hostage to their decision to stay.
Onboarding Takes Forever
When critical knowledge is siloed, you can't scale onboarding. A new engineer joins. They need to learn the codebase. The person who built it isn't available. So the new engineer reverse-engineers from code.
This takes weeks. The person who built it could explain in 2 hours. But they're busy.
Senior engineer onboarding failure costs $240K per incident. When caused by knowledge silos, you're spending half a million dollars per quarter on failed onboarding.
Everything Blocks on the Silo Holder
You're building a feature that touches the payment system. But the payment architect is in meetings. You wait.
Nobody else understands it well enough to unblock you. Your entire team is blocked on one person's availability.
This happens at scale. If 3-4 people know critical systems, the entire team bottlenecks on their attention.
Velocity drops. Urgency increases. People get frustrated.
You Can't Parallelize Work
Two teams want to work on different parts of the same system. But there's only one person who understands it. So only one team can work at a time. The other waits.
You can't parallelize. You're forced into sequential dependencies. Shipping slows.
Risk Concentrates on One Person
That knowledge holder:
Becomes burned out (they're in every meeting, every code review, every decision). Becomes a target for poaching (competitors know they're valuable). Becomes a liability (if they have a bad day, critical decisions get made badly). Becomes resentful ("Why does everything go through me?").
Eventually they leave. You didn't see it coming because you needed them too much to notice the signs.
How Silos Form
Not intentional. They form because:
-
Someone specialized early. "You're good at database stuff. Do the database." Now they're the database person.
-
They solved the hard problem. Built the critical system. Now they maintain it. Because they know it best.
-
Knowledge transfer was never prioritized. Once the system works, it's done. Knowledge transfer is never scheduled.
-
Turnover concentrated it. People who worked on the system left. Knowledge got more concentrated.
-
The system got more complex. Started simple. Now it's complex. Only one person understands all of it.
Distributing Knowledge Deliberately
1. Pair Programming on Critical Systems
When the knowledge holder works on the critical system, someone else should pair with them. That person learns the system. The knowledge holder gets a fresh perspective. Code quality improves. Knowledge gets distributed.
Pair programming on critical systems should be mandatory, not optional.
2. Code Review That Transfers Knowledge
When the knowledge holder reviews code, they should explain context:
"I suggested this pattern because..." "This is important because..." "Watch out for this edge case because..."
Code review becomes a teaching opportunity.
3. Rotate Team Assignments
Don't let people specialize too early. Rotate assignments.
"You built the payment system. For the next quarter, someone else maintains it while you build the notification system. Then rotate again."
This ensures multiple people know each system.
4. Document Critical Decisions
When major decisions are made, document them. Not long. A paragraph: "We chose this approach because X. Alternative was Y. We preferred X because..."
Now when someone asks, they have context.
5. Make Onboarding a Shared Responsibility
When someone new joins and needs to learn the payment system, don't just have the payment person teach them. Have the payment person teach while a third person documents.
Now two people have learned. You have documentation of what new hires need to know.
6. Use Codebase Intelligence Tools
Glue analyzes your codebase and makes knowledge explicit:
What systems are critical? Who maintains them? How do they connect? What would happen if someone left?
With visibility into knowledge silos, you can prioritize addressing them.
The Case for Distributed Expertise
Distributed expertise doesn't mean everyone knows everything. That's impossible.
It means: every critical system is understood by 2-3 people minimum.
Benefits:
- Resilience. If one person leaves, you're not in crisis.
- Speed. Work doesn't bottleneck on one person.
- Quality. Multiple perspectives improve code quality.
- Onboarding. New people learn from multiple sources.
- Morale. People aren't burned out being the only expert.
- Growth. People grow by learning new systems.
Getting Started
- Map your knowledge silos. Which systems are maintained by one person?
- Prioritize by risk. Which silos are most dangerous?
- Assign a knowledge transfer buddy. Pair the knowledge holder with someone who will learn.
- Document as you go. The knowledge holder documents. The buddy reads and asks questions.
- Rotate slowly. Over the next quarter, the buddy takes on maintenance while the knowledge holder does something else.
This isn't a one-time project. It's continuous practice.
The Cost of Waiting
Knowledge silos don't improve on their own. They get worse.
As systems get more complex, knowledge gets more concentrated. As people specialize, silos deepen.
The time to address silos is now, before they become catastrophic.
Frequently Asked Questions
How do I know if I have knowledge silos? Ask: "If Person X left tomorrow, would their system keep running without crisis?" If the answer is "no," you have a silo.
Isn't specialization a good thing? Specialization is good. Concentration is bad. You want people to specialize in areas they own. But ownership should be distributed, not siloed.
How do I convince the knowledge holder to share? Frame it as reducing their burden, not threatening them. "Your knowledge is too valuable to lose. Let's distribute it so you're not the bottleneck and you can work on harder things."