Answers to the questions, asked during Free Webinar - Using Function Point to estimate software

Q1: What is the expansion for FTR [Ramachandram Vedula] [Q: 8:32 PM]

Vivek Prakash: FTR stands for File Type Reference. Count 1 FTR for each data base file referenced for reading or writing purpose by an EI/EO/EQ.


Q2: What are the ranges for TCF and ECF?[Ravi Nadibail] [Q: 8:52 PM]

Vivek Prakash:  TCF –> 0.6 to 1.3 and ECF ->  -0.25 to 2


Q3: Any example of latest technology, that we cannot use in FPA [kushal  mangal]  [Q: 9:17 PM]

Vivek Prakash: FPA is independent of technology. FPA does not estimate efforts using a specific technology but it estimates the size based on the functionality being delivered to user. As the functionality that user is demanding remain same irrespective of technology selected, size estimation using FPA also does not change. Only Productivity depends upon the technology. Productivity for different technology will be different and therefore when productivity is multiplied with FPA estimated size to get the efforts involved, one gets different efforts for different technology with same size.


Q4: how can we accommodate Engineering activities like reviews and reworks[bharat nutakki]  [Q: 9:17 PM]

Vivek Prakash: Refer answer of previous question. Now engineering activities do not change functionality being delivered to a user but these activities only impact productivity. Benchmark data on productivity published by various organizations normally include standard engineering processes. If you have more regress implementation of software engineering activities your productivity may be lower than benchmark (or higher as the case may be).


Q5: Using function point, estimates are accurate but time taking, is it not?[prashant mattupalli]  [Q: 9:18 PM]

Vivek Prakash: You are right. Normally Function Points take more time to estimate software than other techniques like WBS or UCP but it is more actuate. It also provides a platform to forecast your project metrics based on benchmark data.


Q6: Green is good feature, Red is bad, Amber is slightly bad, Blue is what?[Oscar D’souza] [Q: 9:18 PM]

Vivek Prakash: Blue was a statement, neither positive not negative.


Q7: As you told Submit button is a DET, IS RESET button or NEXT button is also a DET ?[Vaibhav Rastogi] [Q: 9:18 PM]


Vivek Prakash: Submit button is a DET as it is required to invoke the functionality. DET is for invoking the functionality. Even if there are 3 method for invoking the functionality like Submit, F3, Ctrl^I, Only 1 DET will be counted. Next is a navigation button and navigation is not counted. RESET is normally not counted but if it is a specific functionality that user has asked for, it can be counted. It should do more than just refreshing the screen.


Q8: PERT is applied on WBS to improvise and also to assess risk. Can FP address this?[Vijay Kumar Rao] [Q: 9:18 PM]

Vivek Prakash: PERT is used to nullify the expert’s bias as there are considerable chances of this bias in WBS technique. Due to well defined rules in FPA, expert’s bias is already taken care of and therefore it is not required.


Q9: For every type of estimate, customer has few points not to accept. what would be an appropriate answer as per you if customer raises concerns on the parametric data?[Ramachandram Vedula] [Q: 9:18 PM]

Vivek Prakash: It is the productivity that is calculated based on historical data using parametric techniques. If you share only the final outcome of this process, there is a fair possibility that customer may challenge your assessment and process as he/she has no idea how you have arrived on the productivity. However if you keep your process transparent and can share the process of arriving on final productivity, customer may not challenge or it would be difficult. Unseen processes, perception and expertise (if unknown) are normally challenged but customer (or any one) cannot challenge the facts. To reduce concerns, provided as many facts as possible to support your data assessment.


Q10: Can Function point estimates be used for production support and maintenance projects[Sridhar Methukupally] [Q: 9:20 PM]

Vivek Prakash: Definitely! In fact, it is the best technique to use here. We normally face problems especially in the beginning of engagement because we do not have understanding of complete application and therefore we cannot estimate the real impact of the change/fix. Function Point suggests estimating the application first. This helps us to understand the size of the application which in turn helps us to estimate work force we require. FPA has specific formulas for calculating enhancement function points based on size of the application. Every time we estimate enhancement or fix, we have better estimate.


Q11: Why cannot use latest technology in FPA [kushal  mangal] [Q: 9:22 PM]

Vivek Prakash: As explained above in Q3, FPA estimation is independent of technology. You can use it for any technology. Please refer Q3.


Q12: Providing a message is also an element.. like Confirm/Error message.. so Invalid age or Invalid Name  message on fields of a screen is also an ELEMENT[Vaibhav Rastogi]] [Q: 9:23 PM]

Vivek Prakash: Providing response to user post transaction is a requirement. Therefore if you provide a confirmation message or error or any other message in response to the transaction, it is one DET. Irrespective of how many messages or errors need to be displayed to user post a transaction, it will always be 1 DET.


Q13: Even though we do our size estimates by using FP. If a PM is preparing the project plan he should be doing WBS right. [bharat nutakki] [Q: 9:26 PM]

Vivek Prakash: Preparing a detailed WBS for good planning is almost mandatory. A detailed WBS gives us better understanding of the project scope. We only advise that estimating based on WBS is not very effective.


Q14: Qualifiers to arrive at the weightage for EI/EO/EQ/Complexity is it standard? If so, who publishes it? [Vijay Kumar Rao] [Q: 9:26 PM]

Vivek Prakash: Function points were defined in 1979 by Allan Albrecht at IBM and these weights were assigned by him based on his study. They have not changed since then. There were some studies to calibrate these weights but none of them was adopted by industry as of now.


Q15: My organization uses WBS and FP both..but for host application in COBOL..they say it is difficult to use. Is that true ?[Vaibhav Rastogi] [Q: 9:27 PM]

Vivek Prakash: If you refer the answer of previous question (Q14), FPA first proposed in 1979 and at that time, most of the commercial applications used COBOL. In fact COBOL was the most popular language. Also as described in answer of Q3, FPA is independent of technology or programming language.


Q16: Is bench mark differing from Development estimates to Support Estimates? from my point of view they should differ[prashant mattupalli]  [Q: 9:29 PM]

Vivek Praksah: I am not very clear about the question but benchmarks are different for development and support activities.


Q17: Can u share the formulas for production support and maintenance projects[Sridhar Methukupally]  [Q: 9:29 PM]

Vivek Prakash: As far as formulas are concerned, you can easily get them by googling over the net. For ready reference, following formula is used for estimating enhancement

Enhancement (aEFP) = [(ADD + CHGA + CFP) x VAFA] + (DEL x VAFB)

Where ADD = added functionality, CFP = conversion functionality, CHGA = UFP of changed functionality after enhancement,

CHGB = UFP of changed functionality before enhancement, DEL = deleted functionality, VAFA = VAF after enhancement, VAFB = VAF before enhancement.


Q18: Will FP estimates works for fixed bid Agile Projects?[bharat nutakki] [Q: 9:33 PM]

Vivek Prakash: Normally Fixed bid and Agile do not go together. Agile is recommended where requirements are evolving and when requirements are evolving, one cannot bid a fixed price. As explained in answer of Q3, FPA is technology or project management style independent.


Q19: Thanks a lot for your presentation, it really helped !! Can we have ur email id ??[Vaibhav Rastogi] [Q: 9:34 PM]

Vivek Prakash: Sure, you can always write to me on If you have any question, please send it to or just press “Add your comment” below and submit your question. I will try my best to respond at the earliest.