The take-away was that a strategy may play out on paper, but the only way to truly test the validity of your product is to put it in front of customers.

WSJ: Lessons GrubHub's CEO Learned Using Freemium

The assumptions test the validity or viability of 1.

FORBES: Japan Confronts Fiscal Reality: Consumption Tax Hike Agreed

If Ms. Rivlin could be called upon now to analyze the numbers to test the validity of purchasing a large private provider like HCA, in a manner that would be credible to President Obama, Democrats, Republicans and everyone else it is my opinion that facts would demonstrate that a dual public system is the silver bullet for fixing healthcare.

FORBES: Why Healthcare Reform Matters to Occupy Wall Street

We can recognize the thought bubble as an unspoken assumption and seek new data to test it for validity.

FORBES: Eliminate Your But!

Buying a diamond ring soon after buying petrol results in an even higher risk score: thieves often test a card's validity with a small purchase before buying something much bigger.

ECONOMIST: Computing

However, Ponting questioned the validity of a seven-match series with every other major Test-playing nation in South Africa preparing at altitude for the two-week tournament.

BBC: Ashes loss still hurts - Ponting

There is something deeply contradictory about Walter Mischel a psychologist who spent decades critiquing the validity of personality tests inventing the marshmallow task, a simple test with impressive predictive power.

NEWYORKER: Don��t!