A red flag often refers to a warning signal, usually used in medical diagnostics or for rating the creditworthiness of customers at a commercial bank. But what would be the (possibly idiomatic) opposite of it?
Let's say I want to explain that a cancer diagnosed person shows some symptoms during a therapy that may be seen as positive signals for the therapy leading to full healing.
The patient shows symptoms that are positive signals for full recovery.
Or I want to acknowledge a person's marital status, yearly income, employment period as positive signals that increase the probability of finally granting them a loan.
The customer's long-time employment is a positive signal for a high creditworthiness.
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