The Outdoor Situational Fear Inventory (OSFI) has been used extensively to measure the social-, physical-, and environmental-based fears of participants in Outward Bound and in college outdoor education programs. The OSFI uses a continuum scaling method in which respondents place a slash mark on a 10-centimeter line representing a continuum from "not at all anxious" to "very anxious." The continuum-scaled OSFI presents several problems: labor-intensive measurements, artificial sense of precision, and difficulties in converting to verbal description. As an alternative, a certainty scaling method was developed in which respondents agree or disagree with a statement and then rate the strength of their opinion from 1 to 5. Responses are then converted to numerical values ranging from 1 to 10. Both forms of the OSFI were administered to 162 college students on the first day of 2-week outdoor adventure programs. Half of subjects completed the continuum version first, then the certainty-scaled OSFI; the other half did the opposite. With either scaling method, the OSFI and its social-fears and physical-fears subscales were reliable as measured by Cronbach's alpha. The order of administration had no effect on scores. The relationships of the two instruments' overall and subscale scores were strong. (SV)