Scheduling of construction projects with an uncertainty content requir
es that the scheduler's subjective knowledge of various factors that m
ight influence the duration of the activities comprising the project i
s incorporated. Depending on the participating factors and their signi
ficance, a different duration outcome is often observed for each activ
ity. To include this uncertainty in the schedule, a statistical distri
bution is frequently used. This paper presents a system based on the p
remise that part of the information available, when duration distribut
ion is being estimated, exists in a subjective form. We present an aut
omated system that requires the modeler to specify the activity's mini
mum and maximum times and a set of linguistic descriptors of the exter
nal factors that are suspect of influencing the duration. The lower an
d upper end point estimates are often available from familiarity with
the technology used, physical and logical constraints, or a combinatio
n of these situations. The subjective information collected by the mod
eler is modeled as fuzzy parameters and is quantified using fuzzy set
theory. The result of the fuzzy set analysis is a sample of activity d
urations from the underlying distribution, which is then used to chara
cterize the first two moments of that distribution. Since earlier rese
arch has shown that the beta distribution provides an adequate represe
ntation for construction durations, the end points specified by the us
er and the two moments resulting from the fuzzy set analysis are used
to fit a beta distribution. The system then allows the user to visuall
y assess the quality of the fit and modify the shape of the beta densi
ty using the visual interactive beta estimation system. The paper also
presents a practical construction scheduling application to demonstra
te the use of the developed system.