Function Point Analysis Certification tips
Methodology of calculating the function points
We need to understand a system first with respect to the function points for that consider an application model as below for measuring the function points.
Now to calculate the function points we need to follow the following steps:
Measure the application boundary
The application boundary defines what is external to the application.
It is dependent on the users external business view of the application and not on the technical and/or implementation consideration
 Identify the data functionalities (ILF and EIF)
User identifiable group of data; logically related and maintained with in the boundary of the application through one or more elementary process is know as ILF.
User identifiable group of data, logically related, referenced by the application but maintained with in the boundary of different application is known as EIF.Few other terminologies of RET and DET are to be understood here as well to determine the functionpoints.
A RET (record element type) is a user recognizable subgroup of data elements with as ILF or EIF
A DET (data element type) is a unique user recognizable, non-repeated field either maintained in an ILF or retrieved from an ILF or ELF.
Identify the transaction functionalities (EI, EO, EQ)
All the tree Transactional functionalities are âelementary processesâ
An Elementary Process is the smallest unit of activity that is meaningful to the user(s).
The elementary process must be self-contained and leave the business of the application in a consistent state.
An EI (External Input) is an elementary process of the application which processes data that entersfrom outside the boundary of the application. Maintains one or more ILF.
An EO (External Output) is an elementary process that generates data that exits the boundary of the application (i.e. presents information to the user) through processing logic, retrieval of data through ILF or EIF. The processing logic contains mathematical calculations, derived data etc.
An EQ (External Query) is an elementary process that results in retrieval of data that is sent outsidethe application boundary (i.e. present information to the user) through retrieval of data from ILF or EIF. The processing logic should not contain any mathematical formula, derived data etc.
Using the above data we can calculate the UFP (Unadjusted Function Points)
After all the basic data & transactional functionalities of the system have been defined we can use the following set of tables below to calculate the total UFP.
Now for each type of Functionality determine the UFPâs based on the below table.
For EIâs, EOâs & EQâs determine the FTRâs and DETâs and based on that determine the Complexity and hence the Number of UFPâs it contributes. We have to calculate this for all the EIâs, EOâs & EQâs.
File Type Referenced (FTR)
File Type Referenced (FTR)
File Type Referenced (FTR)
 For ILFâs & EIFâs determine the RETâs and DETâs and based on that determine the Complexity and hence the Number of UFPâs it contributes. We have to calculate this for all the ILFâs & EIFâs.
Internal Logical File (ILF)
Record Element Types (RET)
 External Interface File (EIF)
Record Element Types (RET)
Once we have the score of all the Functionalities we can get the UFP as
UFP = Sum of all the Complexities of all the EIâs, EOâs EQâs, ILFâs and EIFâs
Further the calculation of VAF (Value added Factor) which is based on the TDI (Total Degree of Influence of the 14 General system characteristics)
TDI = Sum of (DI of 14 General System Characteristics) where DI stands for Degree of Influence.
2. Distributed Data Processing
4. Heavily Used Configuration
These GSC are on a scale of 0-5
Once the TDI is determined we can put it in the formula below to get the VAF.
VAF = 0.65 + (0.01 * TDI)
Finally the Adjusted Function Points or Function Points are
Now these FPâs can be used to determine the Size of the Software, also can be used to quote the price of the software, get the time and effort required to complete the software.
Effort in Person Month = FP divided by no. of FPâs per month (Using your organizations or industry benchmark)
Schedule in Months = 3.0 * person-month^1/3
For e.g. for a 65 person month project
Optimal Schedule = 3.0 * 65^1/3 ~ 12 months
Optimal Team Size = 65 / 12 ~ 5 or 6 persons
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