To make more effective decisions, develop disagreement rather than consensus.  Disagreement provides alternatives and makes you think more deeply about the issue.  In fact, if you don’t have disagreement, you’re not ready to make a decision.  In The Essential Drucker: The Best of Sixty Years of Peter Drucker’s Essential Writings on Management, Peter F. Drucker writes about encouraging disagreement rather than consensus to helps make more effective decisions.
Don’t Make a Decision Unless There’s Disagreement
Drucker writes that you should not make a decision unless you’ve considered alternatives:
Unless one has considered alternatives, …

How will you measure whether your decision will be effective?  To make the most effective decisions, you need to know what to measure. You also need to select among alternatives of measurement so that you can truly understand what’s at stake.  In  The Essential Drucker: The Best of Sixty Years of Peter Drucker’s Essential Writings on Management , Peter F. Drucker writes about how you need to figure out the most appropriate and relevant measurements.
What is the Criterion of Relevance?
The most effective decisions are made by finding the appropriate measurement.  …

How do you make more effective decisions?  Do you start with the facts?  To make effective decisions, you first start with opinions.  You gather facts based on what’s relevant.  You then test opinions against reality.   In The Essential Drucker: The Best of Sixty Years of Peter Drucker’s Essential Writings on Management, Peter F. Drucker writes about making more effective decisions.
Decisions are Judgements
Drucker writes that a decision is a judgment:
A decision is a judgement.  It is a choice between alternatives.  It is rarely a choice between right and wrong.  It is …