Short answer
Say the message in the first thirty seconds, with a specific example, and then stop talking. Softening the opening is what causes engineers to leave performance conversations believing everything is fine - the single most common failure in this conversation is that the message was never actually received.
Almost every new engineering manager delivers their first performance conversation badly in the same direction: too soft, too hedged, too padded with reassurance. The manager leaves relieved that it went well. The engineer leaves thinking they had a slightly odd but basically positive chat. Three months later there is a formal process and the engineer is genuinely blindsided - which is a management failure, not theirs.
Why the Sandwich Fails
The feedback sandwich - praise, criticism, praise - is designed to reduce the discomfort of the person delivering it. Under stress people remember the first and last things they hear, so the structure reliably buries the only part that mattered. If someone can leave the conversation unsure whether there was a problem, the structure has failed.
Open with the message
Say what this is in the first two sentences, before any context.
The opening
"I want to talk about your performance, and I want to be direct because I don't think it would be fair to be vague. The work over the last two months hasn't been at the level I need for this role, and I want to walk through what I'm seeing and hear your side of it."
Then stop and let them respond. The silence will be uncomfortable and you must not fill it - filling it is how managers accidentally soften the message back into ambiguity.
Bring specifics, not characterisations
"You're not being proactive" is unactionable and feels like a personality judgement. Replace every characterisation with an observable event:
- Instead of "your code quality is poor" → "the last three pull requests each needed more than ten rounds of review, mostly on things covered in the style guide."
- Instead of "you're not communicating" → "the checkout work was blocked for six days before I found out, and I found out from Sam rather than from you."
- Instead of "you're not senior enough" → "for the last four projects, someone else broke the work down before you started. At this level I need you to do that part."
Two or three concrete examples are enough. A long list reads as a case being built and puts people straight into defence.
Then genuinely listen
Ask "what's your read on this?" and mean it. Reasonably often there is context that changes the picture - an undisclosed health problem, a family situation, a dependency they were blocked on, or an instruction from someone else that contradicted yours. You are not obliged to change your assessment, but you are obliged to hear it before finalising it.
Agree what changes, specifically
End with observable expectations and a date:
- What good looks like: "Pull requests merge within two rounds of review."
- By when: "I want to see that consistently over the next six weeks."
- How you will check: "We'll review it together in our 1:1 every fortnight."
- What support exists: "I'll pair you with Priya on the next two, and I'll clear the on-call rotation for this month."
Send it in writing the same day. Not as a formal warning, but because memory is unreliable in emotional conversations and both of you need the same record.
Do it early
The kindest version of this conversation happens the first time you notice a pattern, when it is small and fixable and there is no formal process attached. Managers who wait until it is undeniable have removed the opportunity to fix it, and by then the conversation is about consequences rather than improvement.
Frequently asked questions
How do you tell an engineer their performance isn't good enough?
Say it in the first two sentences with a specific example, then stop and listen. Softening the opening is the most common failure - it lets people leave believing the conversation was broadly positive when it was not.
Should I use the feedback sandwich?
No. Praise-criticism-praise exists to make the deliverer comfortable, and under stress people remember the beginning and end, which buries the message. Be direct, be specific, and be kind in your tone rather than in your structure.
What if the engineer gets defensive or upset?
Expect it and do not retreat. Pause, acknowledge it - "I know this is hard to hear" - and hold the message. Softening under emotional pressure teaches that pushback makes feedback disappear, and it is the moment most new managers lose the conversation.
When should I start a formal performance improvement plan?
After clear, specific, documented feedback has been given and a reasonable period has passed without change. A PIP should never be the first time someone learns there is a problem - if it is, that is a management failure rather than a performance one.