Quick Reference

Red flags, decision frameworks, and checklists for when you need answers fast.

Project Red Flags

Spot trouble early: These are warning signs that a project is headed for failure. One or two? Pay attention. Multiple? Intervention required.

Requirements Red Flags

  • "We'll figure out requirements as we go"
  • Requirements change weekly with no process
  • No one can explain why a requirement exists
  • Requirements conflict with each other
  • "The customer will tell us when they see it"

Design Red Flags

  • "Let's make it generic for future use cases"
  • No trade studies, just gut feelings
  • Margins below 10% or completely unknown
  • "We'll optimize later" (spoiler: you won't)
  • Architecture changes during implementation

Process Red Flags

  • No code reviews or peer checks
  • Testing happens only at the end
  • Documentation is "we'll catch up later"
  • Meetings to plan meetings to discuss meetings
  • Decisions made by committee, no ownership

Team Red Flags

  • Key person is single point of failure
  • Engineers padding estimates 3-5x
  • Constant firefighting, no time to think
  • "That's not my job" mentality
  • Finger-pointing instead of problem-solving

Schedule Red Flags

  • Schedule created by management, not engineers
  • No buffer for integration or testing
  • Delivery date set before requirements defined
  • Heroic effort required to stay on track
  • Schedule slips every week but deadline doesn't move

Customer Relationship Red Flags

  • Can't get access to actual end users
  • Requirements from sales, not operations
  • Customer changes priorities daily
  • Every request treated as "scope creep"
  • Adversarial relationship, not collaborative

Decision Framework: When to Act

Not all decisions are equal: Know which decisions are reversible (experiment freely) vs irreversible (think carefully). Jeff Bezos calls these "one-way doors" vs "two-way doors."
Decision Type Reversible? How to Decide Examples
Type 1: Critical & Irreversible No or very expensive Slow, deliberate, gather data, review with team System architecture, hardware platform, major vendor selection
Type 2: Important but Reversible Yes, with moderate effort Decide quickly, implement, evaluate, adjust if needed Algorithm choice, data structure, module interface
Type 3: Low Impact & Reversible Yes, easily Just do it, iterate based on results Variable names, comment style, file organization
Avoid analysis paralysis: Don't treat Type 3 decisions like Type 1. Perfect is the enemy of good enough. Make the call, move forward, adjust if wrong.

Troubleshooting Checklist

Systematic debugging: When things break, don't randomly change variables hoping for improvement. Follow a systematic process.
5-Step Troubleshooting Process
  • 1. Reproduce the problem: Can you make it fail consistently? If not, you can't verify a fix.
  • 2. Isolate variables: Change one thing at a time. Which component/condition causes failure?
  • 3. Form hypothesis: Based on evidence, what's the most likely cause?
  • 4. Test hypothesis: Make targeted change. Does it fix the problem? Why or why not?
  • 5. Root cause analysis: Don't just fix symptoms. Why did this happen? How do we prevent it?

Common Debug Mistakes

Don't Do This

  • Change multiple things at once
  • "Try this" without understanding why
  • Fix symptoms, not root cause
  • Assume "it works on my machine" is sufficient
  • Skip documentation of fix

Do This Instead

  • Change one variable, observe result
  • Form hypothesis before testing
  • Understand mechanism of failure
  • Test in target environment
  • Document problem, cause, and solution

Quick Formulas & Conversions

Power & Electrical

Formula Use Case
P = V × I Power (Watts) = Voltage × Current
V = I × R Ohm's Law: Voltage = Current × Resistance
Energy (Wh) = Power (W) × Time (h) Battery capacity calculations
dB = 10 × log₁₀(P₁/P₂) Power ratio in decibels

Data Rate & Bandwidth

Conversion Value
1 Byte 8 bits
1 Kilobyte (KB) 1,024 bytes (2¹⁰)
1 Megabyte (MB) 1,048,576 bytes (2²⁰)
1 Gigabyte (GB) 1,073,741,824 bytes (2³⁰)
1 Gbps throughput ~119 MB/s (divide by 8.4 for overhead)

Project Kickoff Checklist

Start every project with these questions answered: If you can't answer these, you're not ready to begin.

Problem Definition

  • What problem are we solving?
  • Who is the end user?
  • What does success look like?
  • What happens if we fail?
  • Why is this important now?

Requirements & Scope

  • Do we have written requirements?
  • Are they testable and measurable?
  • Who approves changes to scope?
  • What's in scope vs out of scope?
  • What are the acceptance criteria?

Constraints & Resources

  • What's the budget?
  • What's the timeline?
  • Who's on the team?
  • What tools/infrastructure do we have?
  • What are the technical constraints?

Risks & Dependencies

  • What could go wrong?
  • What are we assuming?
  • What do we depend on externally?
  • Where's the technical risk?
  • How do we mitigate top risks?

Code Review Checklist

What to look for in reviews: Code reviews aren't about finding typos—they're about catching logic errors, design flaws, and maintainability issues.

Correctness

  • Does it meet the requirement?
  • Are edge cases handled?
  • Error handling present and correct?
  • Resource leaks (memory, file handles)?
  • Thread safety if multi-threaded?

Design & Maintainability

  • Is the approach reasonable?
  • Code readable and well-structured?
  • Comments explain "why" not "what"?
  • Avoid premature optimization?
  • Consistent with codebase style?

Testing & Documentation

  • Are there unit tests?
  • Do tests cover edge cases?
  • Is the API documented?
  • Are assumptions stated?
  • Does it impact other modules?

Common Sense Checks

Sanity Test Your Results

Before accepting any calculation, measurement, or result—ask: Does this make sense?

Examples of Sanity Checks
  • Power consumption: 50W for a microcontroller? Check your math. Should be milliwatts.
  • Data rate: 10 Gbps over USB 2.0? Impossible. Max is 480 Mbps.
  • Temperature: Sensor reading 300°C in room temperature? Calibration issue.
  • Timing: Boot time 0.003 seconds? Measurement error or wrong units.
  • Cost: Component costs $0.05? Is that per 1000 units? Check MOQ.
  • Distance: Signal propagation 500ms over 10m cable? Speed of light says no.
Order of magnitude checks: If your answer is off by 10x or 100x, something's wrong. Always verify units, conversions, and assumptions before trusting results.

Useful Acronyms & Terms

Acronym Meaning Context
COTS Commercial Off-The-Shelf Buy instead of build
NRE Non-Recurring Engineering One-time design/development cost
MTBF Mean Time Between Failures Reliability metric
RTM Requirements Traceability Matrix Requirements to tests mapping
PDR Preliminary Design Review Review system architecture
CDR Critical Design Review Review detailed design before build
TRR Test Readiness Review Ready for formal testing?
ConOps Concept of Operations How system will be used
ICD Interface Control Document Defines interfaces between systems