It is called a cascade because each stage allows the development of the following, the most important the first two because they incorporate all information about the problem and guide the solution developed through the program (Chataway 2004, p. 124). The last stage, Maintenance is perhaps the most expensive, since unfortunately, is to use a program when discover most of the failures of the same but, why does this happen? Why not prevent possible failures that may arise later? Everything is due to the lack of planning. And we have said, if the first stages fail or are not well structured, the rest of process is not as expected and an analysis and design poor people will notice when using the solution implemented (Chataway 2004, p. 127).
它被称为一个级联的，因为每一个阶段，允许以下的发展，最重要的前两个，因为他们将有关该问题的所有信息，并引导通过该程序开发的解决方案（Chataway2004年，第124页）。最后阶段，维护也许是最昂贵的，因为不幸的是，使用一个程序，当发现大多数的失败一样的，但为什么会出现这种情况呢？为什么不能防止可能出现的故障，以后可能出现吗？一切是由于缺乏规划。我们已经说过，如果第一阶段没有或没有得到很好的结构，其余的过程并不像预期，分析和设计的穷人会发现当使用解决方案（Chataway2004年，第127页）。
