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mlmentorship

Tell me about a time you disagreed with someone senior

The standard behavioral question. The interviewer is checking whether you can hold technical positions, push back productively, and update on new information.

Published · 7 min read ·Core ·Mixed

Behavioral / leadership · active recall

Practice before you read

3 minutes. Answer the exact question in 90–120 seconds, then reserve detail for follow-ups.

Back to my workbook How practice works

Behavioral / leadership · closed-book attempt

Tell me about a time you disagreed with someone senior

Answer the exact question in 90–120 seconds, then reserve detail for follow-ups.

Problem

Context. An interviewer asks about a real disagreement; the fictional choice below provides a rehearsal of the decision mechanics. Task. Explain the competing goals, gather deciding evidence, identify the decision owner, and describe the outcome and follow-through. For the rehearsal, decide which option currently satisfies the requirements and what new evidence could reopen the choice. Constraints. Mandatory processing-region rules cannot be traded away for speed or cost without authorized requirement changes. Use your own experience in an interview, distinguish facts from assumptions, and represent the other position fairly. Use this fictional rehearsal, not a personal project claim: | Option | Latency | Cost | Approved processing region? | | --- | ---: | ---: | --- | | A | 80 ms | $100,000 | Yes | | B | 60 ms | $70,000 | No | The requirements are latency below 100 ms and an approved processing location. Someone favors B's speed and cost; you favor A's compliance with the current boundary. What evidence resolves the choice? What could reopen it?

03:00recommended time

Closing or reloading clears the scratchpad. Only score, weak rubric dimensions, attempt count, and retry date can be stored locally.
Reading depth

Explain a technical disagreement with a senior colleague through both positions, the deciding evidence, and your role in the resolution.

Problem

Context. An interviewer asks about a real disagreement; the fictional choice below provides a rehearsal of the decision mechanics.

Task. Explain the competing goals, gather deciding evidence, identify the decision owner, and describe the outcome and follow-through. For the rehearsal, decide which option currently satisfies the requirements and what new evidence could reopen the choice.

Constraints. Mandatory processing-region rules cannot be traded away for speed or cost without authorized requirement changes. Use your own experience in an interview, distinguish facts from assumptions, and represent the other position fairly.

Use this fictional rehearsal, not a personal project claim:

OptionLatencyCostApproved processing region?
A80 ms$100,000Yes
B60 ms$70,000No

The requirements are latency below 100 ms and an approved processing location. Someone favors B’s speed and cost; you favor A’s compliance with the current boundary. What evidence resolves the choice? What could reopen it?

Picture: Evidence Before Commitment

The shared memory limit rejects the faster but oversized cache

The memory limit rejects an option, not its advocateOn one shared scale, faster cache A breaches 8 GB. Cache B fits; reopening A needs new evidence of feasibility.The same wall applies to both choicesCache A: 9 / 8 GBStops at the wallCache B: 6 / 8 GBFits this bankChoose Cache B
Derivation
Change the decision when evidence changes the shared constraintTwo zero-based bars share the same gigabyte scale. Fictional faster cache A occupies nine units and crosses the eight-gigabyte limit. Smaller cache B occupies six and fits. The decision owner chooses feasible B, retains required reviews, and can reopen A only when evidence shows it fits within the shared limit. The constraint rejects an option rather than its advocate.FICTIONAL COMPARISON; ONE SHARED GB SCALEA: faster9 GBB: smaller6 GB8 GB limitA crosses the limit. B fits the sameconstraint.Owner selects feasible B.Required reviews remain.Reopen A only when evidence shows it fitswithin 8 GB.The constraint rejects an option, not itsadvocate.
Read it this way: The shared constraint, not seniority, selects the feasible option in this fictional case. Record what evidence would reopen the choice. Required reviews remain.
Check: Which observation would change the preferred option, and who owns the final bounded decision?
Read it this way: On one shared scale, faster cache A breaches 8 GB. Cache B fits; reopening A needs new evidence of feasibility.
Can a speed advantage make the ninth memory unit fit?

Apply the Constraints Independently

Both 80 and 60 ms are below 100 ms. B’s lower cost cannot compensate for its failed region requirement. The owner can select A or investigate an approved B configuration. Record regional approval as a possible reopening condition; do not assume it will occur.

Change 1: The Other Approach Is Selected

New task. The owner chooses another defensible, permitted approach.

Picture and change. Execute it responsibly; observe the distinguishing metrics and agreed revisit condition.

Check. Commitment does not require pretending your earlier uncertainty vanished or waiting to say you were right.

Use when. Your recommendation is not selected.

Change 2: The Decision Crosses a Hard Boundary

New task. The chosen action violates a non-negotiable safety, privacy or integrity rule.

Picture and change. Use required review/escalation and keep appropriate records; do not treat ordinary commitment as authorization.

Check. An owner cannot waive every external duty.

Use when. The issue is a prohibited action, not an ordinary preference.

Failure: A Scripted Victory or Conversion

A story fails to explain the decision when it omits credible opposition or invents a change of mind.

Transfer Check

Must a disagreement end with a third option C?

Reasoned Answer

No. Evidence can support retaining A or B. Synthesis is a possible result, not a required narrative.

What the question actually tests

Describe technical conviction, productive challenge and willingness to update when warranted. Do not fabricate disagreement or opposing competence to fit a story.

Evidence Worksheet

Use STAR(L) as optional prompts, not memorized filler:

PromptRecord
Situation/taskShared goal, constraints, responsibility and decision rights
PositionsStrongest actual argument for each option
ActionYour discussion, document, test, collaboration or escalation
EvidenceMeasured facts, assumptions and remaining uncertainty
Decision/resultOwner, selected option, what shipped and observed outcome
LearningWhat changed or remained; revisit condition

Separate personal/team contributions and observed/counterfactual impact. When a decisive test is unavailable, state criteria and risks instead of inventing certainty. Technical versus strategic topic labels do not determine scope or company level.

Check the Account

Can another person probe the technical decision and reconstruct your actual contribution? Neither changing your view nor creating C is mandatory.

Missing Evidence

Replace generic advocacy with the missing rationale, action, outcome limit or reopening rule.

A trap to avoid

Respectful representation does not require pretending an unsafe proposal is acceptable. Avoid caricaturing the other person; explain the disputed reasoning and constraint.

Common follow-up

What if your recommendation lost? Explain allowed execution, distinguishing observations and agreed review, not a grudge.

Sources

Related: The 5 things every applied scientist interview is testing for, senior through senior-principal ML scope.

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