Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

1. INTRODUCTION To deal with the risks of the spaceflight project, it isnecessary for the analyzer to estimate the relevancebetween the cost and the schedule. Usually, the schedu-le-cost correlation coefficient is directly selected appoi-nted according to the experts. This may bring big errorssometimes. So it is of most importance to amend it basedon historical statistics, approximately. 2. CONDITIONAL PROBABILITY DISTRIBUTIONFUNCTIONS BETWEEN SCHEDULE AND COST A…

Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the ln(schedule) and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the ln-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the ln-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.