May the force (field analysis) be with you

Yea you guessed it, I am a Star Wars fan. And I'd like to talk to you about it some more but we have more important issues pressing like discussing what force field analysis is and how it has no relation to Star Wars.
OK, so force field analysis is used for looking at all the forces for and against a decision, so says
http://www.mindtools.com/pages/article/newTED_06.htm. Basically it helps enforce the forces supporting your decision and reduce the impact of oppositional forces (ie people, time constraints, lack of supplies, etc). So here we go again with another graph and possible conflict in deciding how much each force is worth to you (that seems to be a commonality lately don't you think).
Like many of the same past examples, you have a decision to make and in the example on the website, your deciding to upgrade a factory with spanky new manufacturing equipment. You judge what forces support your decision and give them a score of 1-5 and what forces oppose your decision. Going with the example, one "negative" force is the fear of the staff of the new technology with a score of 3. Now how did the decision maker come to think that score was appropriate? Did he/she take a general survey of the staff or just guess that 3 was a good guess. Also with the purchase of new equipment one has to consider the salvage cost of the equipment after it's life cycle is complete which would impact the cost, hopefully lowering the score some. So when making a large decision that is impacted by different forces with one being the time and efforts of employees and people, how do you go about determining how much of a score is warranted. And remember that when making such a large scale and impacting decision, how will it change the employees' way of life, from simple adjustment due to new tech to if layoffs need to occur. Just a thought.