Contingent future interests have caused considerable confusion in cases in which the holder of the future interest dies before the fulfillment of the condition. This confusion stems from a tendency by some courts to use the word "contingent" as a shorthand way of indicating that the interest holder must survive until a certain time or event. A future interest is correctly said to be "contingent" when it is subject to a condition, in addition to the termination of the prior estate, which must occur before the interest becomes a present estate. The two usages of the word are often overlapping, but they are not synonymous; although a requirement of survival is the most common type of condition rendering an interest contingent, it is only one of many types of conditions which may be imposed.
Michigan Law Review,
Future Interests--Implying a Requirement of Survival in Future Interests: Continued Confusion--Schau v. Cecil,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol65/iss1/10