The condition of being collapsible (or collapsable)(noun)
The extent to which something is collapsible(noun)
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Use "collapsibility" in a sentence
"Y. Risk ratios, but not odds ratios, have a mathematical property called collapsibility; this means that the size of the risk ratio will not change if adjustment is made for a variable that is not"
"But perhaps if an interface were developed that allowed full customization and collapsibility of each feature utilized."
"Studies have concentrated on clinical research across the age spectrum, evaluating upper airway collapsibility during sleep, as well as arousal mechanisms."