To solve the problem you see actually must be break down into the cause and effect. Many theory to solve the problem but actually you can break down by yourself. For Experience people may be can see what is the source of the problem, but for non experience people usually using trial and error. But trial and error method can consume mush time and costly. For simple problem may be just need a short time and may not costly but for a big problem this can be very expensive and need long time. Sometime this is not efficient.
For Example you have problem on your truck, and you are limited by time to finish. If you can't finish your truck in the limit time, you will loose the order because yuor customer will take another vendor. On this cases you must break down your truck problem and must take a right decision, if you make wrong decition, the effect you will loose your order.