If prices slowly retreat rather than collapsing, the bubble definition would be ill-fitting.

FORBES: It Started With Tulips, Now Bubble-Watchers Are Looking To The Bond Market

For example, if one group contains more older patients or more who are seriously ill, the outcome may be influenced by those differences rather than by the treatment itself.

FORBES: Clinical Trial Advice For Investors From Two Pros

Studies have shown that mentally ill people are far more likely to be the victims of violence rather than perpetrators.

WSJ: New York Gun Law's Mental-Health Provision Draws Ire

Currently, health care systems focus primarily on chronic ill health, rather than the preventative measures of living a healthy lifestyle, but this may be the adjustment that both the health care system and insurance companies make as a result of digital health devices.

CNN: Your phone will know you're sick before you do

Because rather than ill-use the weary hordes, retailers are making it worth the trouble for customers to be one of them.

FORBES: Why You're Mad if You Miss Black Friday Madness