Single Decisive Reason (SDR)
For any important decision, isolate the one reason that alone justifies it — a pile of weak reasons is a red flag
- Difficulty
- Easy
- Time to result
- ~days to results
- Steps
- 4
- Confidence
- 95%
A decision-making test: for important choices you should be able to name a single reason that, on its own, supports the decision. If someone can only offer a collection of weak reasons, they haven't yet understood why they want to act. The sheer count and effort of listing many pros or cons biases judgment consciously and subconsciously.
Origin
Rahul Vohra picked up SDR from Reid Hoffman during his time at LinkedIn.
Core principles
- 01Important decisions should rest on one reason strong enough to stand alone
- 02A long list of weak reasons is a bias trap, not a justification
- 03Group settings amplify the bias — they're more risk-averse and consensus-driven
- 04Every decision has an opportunity cost, so a strong single reason should outrank many weak ones
How to run it
- 1
Ask for the single decisive reason
When someone brings a decision backed by multiple reasons, ask: 'What is the single decisive reason?'
- 2
Isolate one reason from the list
If they list three or four things, press: 'If only one of those were true and you still advocated for this, which is it?'
- 3
Apply the counterfactual test
Ask: if this one reason were true and everything else were false, would you still make the decision?
Pro tip Sometimes the answer is still yes — that confirms a strong reason. Sometimes it's no, revealing the case rested on weak reasons.
Watch out Inability to isolate an SDR doesn't mean the decision is wrong — it means the reasoning isn't yet understood.
- 4
Reconsider when no SDR exists
If no single reason survives, treat it as a signal: the outcome may be less likely than assumed, or a strong reason on the opposing side is being hidden by the pile of weak pros.
Pro tip Weigh the opportunity cost — building this for weak reasons means not building something else for a strong one.
In the wild
Vohra notes that writing 3 pros against 10-15 cons lets the sheer number and effort of the cons sway you subconsciously — especially in risk-averse group settings — even when the decision might be right.
→ By forcing an SDR, teams surface whether one reason truly carries the decision or whether they're rationalizing with volume.
Common mistakes
Justifying with a collection of weak reasons
Multiple low-quality reasons rarely add up to a high-quality reason, yet their volume biases the decision.
Letting group consensus manufacture false confidence
Groups drift toward consensus and risk-aversion, inflating the apparent weight of many small reasons.
Is it for you?
Best for
Leaders and teams evaluating important, high-opportunity-cost decisions like what feature to build next
Not ideal for
Low-stakes reversible calls where the overhead of isolating a decisive reason isn't worth it
From the transcript
“SDR is a thinking tool that I picked up from Reed Hoffman during my time at LinkedIn”
“you should be able to identify one one reason that on its own supports the decision”
“all too often we rely on a collection of weak reasons to justify decisions”
“meaning if this was true and all the other things were not true would I still do it”
From the episode
Superhuman's secret to success: Ignoring most customer feedback, manually onboarding every new user, obsessing over every detail, and positioning around a single attribute: speed
Rahul Vohra (CEO)