The traditional Delphi method is one of the effective methods which en
ables forecasting by converging a possibility value through the feedba
ck mechanism of the results of questionnaires, based on experts' judgm
ents. Some points needing revision are: (1) By pinpointing the intuiti
on of the first response on the part of experts, feasible inference va
lues need to be extracted so that the quality-oriented and semantic st
ructure of the responses may be analyzed. (2) By removing the effect c
aused by feedback in the Delphi method, natural and non-converged resu
lts need to be acquired; Moreover, two and more repetitive surveys are
likely to cause a decline in the response rate, which may produce neg
ative effects in the ensuing analyses. (3) In general, as it is repeat
ed, the survey becomes more costly and time-consuming. In order to res
olve these issues, we have identified two kinds of membership function
s in regard to 'the attainable period with a high degree' and 'the una
ttainable period with a high degree'. Next, through the implementation
of the Max-Min Fuzzy Delphi Method and the New Delphi Method via Fuzz
y Integration, we have developed algorithms which enable forecasting a
ttainable periods. Third, we have applied such algorithms to two concr
ete questions, compared the result with one obtained from the Delphi m
ethod, and ascertained the feasible outcome. While more examination ne
eds to be undertaken, the new methods look valid and applicable to fur
ther analyses of other questions and items on questionnaires. While bo
th methods can forecast attainable periods, using these methods simult
aneously as well as the traditional Delphi method, may prove a really
effective result.