The 23-item MUIS-C was developed in 1986 as a modification of the 33-item Mishel
Uncertainty in Illness Scale (MUIS-A). While the original instrument was designed to assess
uncertainty in hospitalized or acutely ill adults, the MUIS-C is intended for use with
community-dwelling chronically ill adults who are not hospitalized and may not be
receiving treatment, or living with their families (Mishel 1997b). Items from the MUIS-A
relating to hospitalization of acutely ill patients were therefore removed from the MUIS-C
(Mishel 1997b). Although validity of the MUIS-C has not been directly measured, its items
are highly similar to those of the original MUIS-A and the validity results from that
instrument have been used to support the MUIS-C (Mishel, 1997b).