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Engineering9 min read

Why Good Engineers Make Bad Decisions (And How to Fix It)

Your smartest engineers are making decisions in the dark. Here's why context matters more than capability.

AM
Adam Marsh
Founder · December 9, 2025
Good engineers making decisions with incomplete information

Your smartest engineers are making terrible decisions. Not because they're incompetent, but because they're operating in the dark.

Good Engineers+Bad Information
=Bad Decisions

It's not a character flaw. It's an information architecture problem.

The Information Asymmetry Problem

Consider a senior engineer designing a new service. They're talented. They're experienced. They know best practices.

What they don't know:

That a similar approach was tried three years ago and failed

That there's a constraint from a regulatory requirement decided last quarter

That another team is building something similar

That the performance characteristics of a dependency have changed

They make the best decision possible given the information they have. Unfortunately, the information they have is incomplete.

Why Information Fails to Flow

1
Information Silos

Teams optimize for local efficiency. The database team knows everything about database decisions. The frontend team knows everything about frontend decisions. Neither knows about the other.

Cross-cutting decisions fall into gaps.

2
Information Decay

Decisions made six months ago are half-remembered. Decisions made two years ago might as well not exist.

Context evaporates faster than code.

3
Information Overhead

There's too much documentation. Most of it is noise. Finding the relevant signal requires knowing what to look for.

If you knew what to look for, you wouldn't need to search.

4
Information Hoarding

Some information stays in heads because writing takes time, having information is power, or "they'll ask if they need to know."

Critical context remains inaccessible.

The Decision Quality Framework

McKinsey research identifies factors that separate good from bad decisions:

What Matters

Speed of decision-making
Quality of available information
Clear decision rights
Commitment to follow-through

What Doesn't Matter (as much as you'd think)

Seniority of decision-maker
Time spent in meetings
Consensus achieved
Analysis paralysis
Good information enables fast, high-quality decisions. Bad information causes slow, poor decisions—regardless of who's deciding.

The Case Study: Knight Capital

$440M
lost in 45 minutes

Knight Capital Group, August 1, 2012

Deployed code that reactivated dormant functionality from eight years earlier. Executed over 4 million erroneous trades.

The engineers who deployed weren't incompetent. But they lacked information:

  • What did the old code do?
  • Why was it kept in the codebase?
  • What flags controlled its activation?

Decisions made years earlier—and never documented—created a time bomb that destroyed the company.

The Pattern: Decisions Without Context

You've seen this pattern play out countless times:

The Pattern: Decisions Without Context

1
Engineer proposes approach
2
Someone vaguely remembers "we tried that"
3
But not the details, or why it failed
4
Team debates based on incomplete information
5
Either: repeat the mistake, or avoid a valid approach

Without documented decisions: past failures teach no lessons, past successes aren't replicable, every decision starts from scratch.

Building an Information Architecture

L1
Decision Records
  • What was decided
  • Why it was decided (constraints, goals)
  • What alternatives were considered
  • What tradeoffs were accepted
L2
Decision Relationships
  • Dependencies: "This decision assumes X from decision Y"
  • Conflicts: "This contradicts decision Z"
  • Supersession: "This replaces old decision Q"
L3
Decision Currency
  • Review dates: When should this be reconsidered?
  • Validity conditions: Under what circumstances does this apply?
  • Staleness indicators: What would trigger review?

The difference between a good and bad decision record:

Bad
"We chose Redis."
Good
"We chose Redis for session storage because we need sub-millisecond reads, expect 10k+ requests/second, and can accept data loss on Redis failure. We considered PostgreSQL (too slow) and Memcached (Redis offers better operational tooling)."

Making Information Findable

Captured information that can't be found is useless. Invest in:

Search
  • Full-text search across decisions
  • Filtered by team, date, topic
  • Semantic search (concepts, not just keywords)
Surfacing
  • Relevant decisions appear when working on related code
  • New engineers get recommended reading
  • Stakeholders notified when related decisions change
Visualization
  • Decision graphs showing relationships
  • Timeline views showing evolution
  • Dependency maps showing impacts

The Counterfactual

Imagine an engineer making a decision with full context versus without:

With Full Context

"I'm designing the new caching layer. Let me check what we've decided before...

Ah, there was a decision three years ago about caching strategy. They chose write-through but noted our workload might shift. Our workload has shifted—we're now 90% reads. And there's a decision from the platform team about Redis standardization.

Given this context, my proposal is..."

Without Context

"I'm designing the new caching layer. I'll use what I learned at my last job..."

Same engineer. Different information. Different decision quality.

The Organizational Shift

Moving from "good engineers figure it out" to "good information enables good decisions" requires:

Cultural Shift
  • Document decisions as they happen
  • Treat documentation as deliverable, not overhead
  • Recognize contributors to institutional memory
Process Shift
  • Decision capture integrated into workflow
  • Review cycles that revisit old decisions
  • Onboarding that includes decision history
Tool Shift
  • Searchable decision repository
  • Relationship tracking between decisions
  • Alerts when decisions might be affected by changes

Your engineers aren't making bad decisions because they're bad at deciding.

They're making bad decisions because they don't have the information they need.

Fix the information, and you fix the decisions.

Ready to document your decisions?

Stop letting architectural knowledge walk out the door. Start capturing decisions today with Arbtr.