Advice on determining the best choice between Parametric and Analogous Estimating
Anonymous
Hi Team,
I am look for advice on how best to determine which methodology is best to use.
If you were updating the Charter with cost estimates and using an estimating technique, would you use analogous, parametric, bottom up while updating the cost estimates.
how would you dissect that question to determine the tool?
i read it like this and would love your feedback:
I have a Charter and I am updating with Cost Estimates so I am in Planning and not integration
Analogous, Parametric, and Bottom up are great but given what i know, i would use Bottom up. if the question said there was another project i had done in the past i would say analogous?
1)is my approach correct
2) how do you pick between analogous and parametric?
Bottoms-up estimating is used where you can break the work down into detailed tasks, and estimate each task. This requires a lot of knowledge about the detailed WBS.
Analogous estimating is where you say task or project A is similar to task or project B which you have historical information about, so use a similar estimate.
Parametric is a bit like analogous but you have enough information to scale a prior work statement based on some variable. For example a road is twice as long as one you have built previously so your materials cost will be twice that of the prior road.
The question doesn't tell you what you already know. It's probably not bottoms-up because you're early enough that you're updating the charter, but it doesn't tell you what information you have to update the cost estimate. Many practice questions that come up in these forums are not well written questions. Saving Changes...
Analogous estimation is appropriate whenever you either don't have all the information to do a detailed estimate or the project is similar enough to a historical one. That's why it lends itself well to being used during the initiation stage for a project.
Remember that all of these techniques can be used at any level of granularity - for the project as a whole, for a control account, a specific work package or a single activity.
If you have detailed information about estimations of the portions of work of the project, you should use parametric estimating. Having estimated the minimum portions of work, you can scale and calculate the estimations of complete work packages, and then the entire project.
For other part, analogous estimating is used when you have general historic information of a past similar entire project or task executed. Saving Changes...
If parametric is possible, you will want to use that or you will most-likely have budget issues. The problem is its not always available or only on a small set of activities. Saving Changes...
To Phuong NamProject Manager| Thyssenkrupp Vietnam LtdHanoi, Hn, Viet Nam
Analogous estimation is less accurate ( -50% to +50% or -25% to +75%), using in initial phase since you have very limited information. It is a form of expert judgement. And it actually uses the information of similar/previous project. Below is quoted from analogous template:
Love can sweep you off your feet and carry you along in a way you've never known before. But the ride always ends, and you end up feeling lonely and bitter. Wait. It's not love I'm describing. I'm thinking of a monorail.
