If you want to buy the project management book mail [email protected]  for more details or call any of our book shops MUMBAI-22078296/97/022-22070989, KOLKATA-22826518/19 HYDERABAD-24756967,24756400,BANGALORE-25587923, 25584641,AHMEDABAD-26421611,BHATINA(PUNJAB)-2237387,CHENNAI-28410796,28550491,DELHI/NEWDELHI-23254990/91,23325760,26415092,24691288.If you want to write to the author directly email at [email protected]
 

Home

(I) Can you explain concept of FTR, ILF, EIF, EI, EO , EQ and GSC ?

Elements of Function Points

Following are the elements of FPA.

Internal Logical Files (ILF)

Following are points to be noted for ILF: -

• ILF are logically related data from user point of view.
• They reside in Internal Application boundary and are maintained through

            Elementary process of application.

• ILF can have maintenance screen or probably not.

Figure: - ILF example

External Interface File (EIF)

• They are logically related data from user point of view.
• EIF reside in external application boundary.
• EIF is used only for reference purpose and are not maintained by internal

       application.

• EIF is maintained by external application.

Record Element Type (RET)

Following are points to be noted for RET

• RET are sub-group element data of ILF or EIF.
• If there is no sub-group of ILF then count the ILF itself as one RET.
• A group of RET’s within ILF are logically related. Most probably with a parent

      child relationship. Example: - Supplier had multiple addresses and every address

      can have multiple phone numbers (See detail image below which shows database

      diagrams).So Supplier, Supplier Address and Supplier phone numbers are RET’s.

                                            Figure: - RET

Please note the whole database is one supplier ILF as all belong to one logical section. RET quantifies the relationship complexity of ILF and EIF.

DET (Data element types)

Following are the points to be noted for DET counting: -

• Each DET should be User recognizable. Example in the above given figure

            we have kept auto increment field (Supplierid) for primary key. Supplierid field

            from user point of view never exists at all , its only from software designing

            aspect, so does not qualifies for DET.

• DET should be non-recursive field in ILF. DET should not repeat in the same

            ILF again, it should be counted only once.

• Count foreign keys as one DET. “Supplierid” does not qualifies as DET but

            its relationship in “supplieraddress” table is counted as DET. So “Supplierid_fk”

            in supplieraddress table is counted as DET. Same folds true for

            “Supplieraddressid_fk”.

File Type Reference (FTR)

Following are points to be noted for FTR: -

• FTR is files or data referenced by a transaction.
• FTR should be ILF or EIF. So count each ILF or EIF read during process.
• If the EP is maintaining an ILF then count that as FTR. So by default you will

      always have one FTR in any EP.

External Input (EI)

Following are points to be noted for EI: -

• It’s a dynamic elementary process [For definition see “Dynamic and Static

            Elementary Process” Section] in which data is received from external

            application boundary.

            Example: - User Interaction Screens, when data comes from User Interface

            to Internal Application.

• EI may maintain ILF of the application, but it’s not compulsory rule.

            Example: - A calculator application does not maintain any data, but still the

            screen of calculator will be counted as EI.

• Most of time User Screens will be EI, again no hard and fast rule. Example: -

            An import batch process running from command line does not have screen,

            but still should be counted as EI as it helps passing data from External

            Application Boundary to Internal Application Boundary.

External Inquiry (EQ)

Following are points to be noted for EQ: -

• It’s a dynamic elementary process in which result data is retrieved from one or

            more ILF or EIF.

• In this EP some input request has to enter the application boundary.
• Output results exits the application boundary.
• EQ does not contain any derived data. Derived data means any complex

            calculated data. Derived data is not just mere retrieval but are combined with

            additional formulae to generate results. Derived data is not part of ILF or EIF,

            they are generated on fly.

• EQ does not update any ILF or EIF.
• EQ activity should be meaningful from user perspective.
• EP is self contained and leaves the business in consistent state.
• DET and processing logic is different from other EQ’s.
• Simple reports form good base as EQ.

External Output (EO)

Following are points to be noted for EO: -

• It’s a dynamic elementary process in which derived data crosses from Internal

            Application Boundary to External Application Boundary.

• EO can update an ILF or EIF.
• Process should be the smallest unit of activity that is meaningful to end user

in business.

• EP is self contained and leaves the business in a consistent state.
• DET is different from other EO’s.So this ensures to us that we do not count

      EO’s twice.

• They have derived data or formulae calculated data.

Major difference between EO and EQ is that data passes across application boundary.

Example: - Exporting Accounts transaction to some external file format like XML or

some other format. Which later the external accounting software can import. Second

important difference is in EQ its non-derived data and EO has derived data.

General System Characteristic Section (GSC)

This section is the most important section. All the above discussed sections are counting

sections. They relate only to application. But there are other things also to be considered

while making software, like are you going to make it an N-Tier application, what's the

performance level the user is expecting etc these other factors are called GSC. These are

external factors which affect the software a lot and also the cost of it. When you submit

a function point to a client, he normally will skip everything and come to GSC first. GSC

gives us something called as VAF (Value Added Factor).

There are 14 points considered to come out with VAF (Value Added factor) and its

associated rating table.

Data Communications

How many communication facilities are there to aid in the transfer or exchange of

information with the application or system?

                    Table   : - Data Communication

Distributed data processing

How are distributed data and processing functions handled?

                      Table   : - Distributed data processing

Performance

Did the user require response time or throughput?

Table   :- Performance

Heavily used configuration

How heavily used is the current hardware platform where the application will be executed?

Table   : - Heavily used configuration

Transaction rate

How frequently are transactions executed; daily, weekly, monthly, etc.?

Table   :- Transaction rate

On-Line data entry

What percentage of the information is entered On-Line?

Table   :- Online data entry

End-user efficiency

Was the application designed for end-user efficiency? There are seven end-user efficiency factors which govern how this point is rated.

Table: - End user efficiency factor

Table   : End user efficiency

On-Line update

How many ILF’s are updated by On-Line transaction?

Table   :- Online update

Complex processing

Does the application have extensive logical or mathematical processing?

Table   :- Complex processing factor

Table: - Complex processing

Reusability

Was the application developed to meet one or many user’s needs?

Table   : - reusability

Installation ease

How difficult is conversion and installation

Table   : Installation ease

Operational ease

How effective and/or automated are start-up, back up, and recovery procedures?

Table: - operational ease

Multiple sites

Was the application specifically designed, developed, and supported to be installed at

multiple sites for multiple organizations?

Table   : - Multiple sites

Facilitate change

Was the application specifically designed, developed, and supported to facilitate change?.

The following characteristics can apply for the application

Table   : Facilitate change factors

Table: - Facilitate change

All the above GSC are rated from 0-5.Then VAF is calculated from the equation below:-

VAF = 0.65 + ((sum of all GSC factor)/100).

Below shown are look up tables which will be referred during counting.

                        Table   :- EI rating table

This table says that in any EI (External Input), if your DET count (Data Element) and

FTR (File Type Reference) exceed these limits, then this should be the FP (Function Point). Example, if your DET (data element) exceeds >15 and FTR (File Type Reference)

is greater than 2, then the Function Point count is 6. The rest down tables also show the

same things. These tables will be there before us when we are doing function point count.

The best is put these values in Excel with formulae so that you have to only put quantity

in the appropriate section and you get the final value.

                                     Table   :- EO rating table

Table   :- EQ rating table

Table   :- ILF rating table.

Steps to Count Function Points

This section will discuss the practical way of counting the FP and coming out with a

Man/Days on a project.

• Counting the ILF, EIF, EI, EQ, RET, DET, FTR (this is basically all sections

            discussed above): This whole FP count will be called as "unadjusted function

            point".

• Then put rating values 0 to 5 to all 14 GSC. Adding total of all 14 GSC to

            come out with total VAF. Formula for VAF = 0.65 + (sum of all GSC factor/

            100).

• Finally, make the calculation of adjusted function point. Formula: Total

            function point = VAF * Unadjusted function point.

• Make estimation how many function points you will do per day. This is also

            called as "Performance factor".

• On basis of performance factor, you can calculate Man/Days

]

 Let’s try to implement these details in a sample customer project.

Sample Customer Project

We will be evaluating the customer GUI. So we will just scope what the customer GUI is all about.

Following is the scope of the customer screen:-

• Customer screen will be as shown below.
• After putting the customer code and Customer name. They will be verified

      credit card check.

• Credit Card check is a external system.
• Every Customer can have multiple addresses.
• Customer will have add, update functionality.

Figure:- Custom screen

There is one ILF in the above screen:

• The customer ILF.

There is one EIF in the above form.

• Credit Card System

Following the ILF counting rules

• ILF are logically related data from user point of view. Customer and Customer

            addresses belong logically to customer category.

• ILF reside in Internal Application boundary and are maintained through

            Elementary process of application. Customer resides in inside application

            boundary as we have full access over it.

So hence goes the counting below for ILF

                                     Table   : - ILF for the customer

EIF lie outside the application boundary.

                       Table   : - EI for the customer

Following EIF rules define in the previous sections:

• It’s a dynamic elementary process [For definition see “Dynamic and Static

            Elementary Process” Section] in which data is received from external

            application boundary. Customer detail is received from external boundary

            that is customer input screen.

• EI may maintain ILF of the application, but it’s not compulsory rule. In this

            sample project Customer ILF is maintained.

• So there are two EI one for Add and one from update.

                                                                  Table   : - EI for the add customer

                                       Table   : - EI for the update customer

While counting EI I have seen many people multiplying it by 3.That means we are going

to do all CRUD functionality (ADD, UPDATE, and DELETE).This is not fair as it just

shows laziness of the Cost estimation team. Here the customer screen has add and update.

I can say the 2 * 6 that's = 12 FP for this EI customer. But later when some refers to your

FP sheet he will be completely lost.

Following are rules to recognize EO: -

• Data should cross application boundary and it should involve complex logic.

Credit card check process can be complex as the credit card API complexity is still not

known. Data that is credit card information crosses from credit card system to Customer

system.

                                    Table   :- EO to check the credit card

Following are rules to recognize EQ: -

• It’s a dynamic elementary process in which result data is retrieved from one or

            more ILF or EIF. For editing the customer we will need to retrieve the customer

            details.               

• In this EP some input request has to enter the application boundary. The

            customer code is inputted from the same screen.

• Output results exits the application boundary. The customer details is displayed

            while the customer is editing the customer data.

• EQ does not contain any derived data. The above customer data which is

            displayed does not contain any complex calculations.

                                    Table   :- EQ to display customer edit

So now, let’s add the total function point got from above tables:

Table   :- Total of all function point

So unadjusted function point comes to 31.Please note I have said this as Unadjusted

function as we have not accounted other variance factor of project (Programmers leaving job, Language we will use, what architecture etc etc).

In order to make it adjusted function point, we have to calculate and tabulate the GSC

and come out with the VAF.

                                         Table: - GSC

This factor affects the whole FP like anything, be very particular with this factor. So now,

calculating the Adjusted FP = VAF * Total unadjusted

Now we know that the complete FP for the customer GUI is 27 FP. Now calculating the

efficiency factor, we say that we will complete 3 FP per day that is 9 working days. So, the whole customer GUI is of 9 working days (Note do not consider Saturday and Sundays in this). I know upper manager people will say make it 7 FP per day and over load the programmer. That’s why programmer works at night.

Considering SDLC (System Development Life Cycle)

Before reading this section please refer to different SDLC cycles  questions in the previous chapters.

The main intention of introducing this section is because quotations are heavily affected

by which software life cycle you follow. Because deliverables change according to SLDC

model the project manager chooses for the project. Example for waterfall model we will

have Requirement documents, Design documents, Source code and testing plans. But for

prototyping models in addition to the documents above we will also need to deliver the

rough prototype. For build and fix model we will not deliver any of the documents and

the only document delivered will be source code. So according to SDLC model deliverables change and hence the quotation. We will divide the estimation across requirement, design, implementation (coding) and testing .In what way the estimation has to divide across all deliverables is all up to the project manager and his plans.

Table   :- Phase wise distribution of effort

The above sample is total 100 % distribution of effort across various phases. But note function point or any other estimation methodology only gives you total execution estimation. So you can see in the above distribution we have given coding as 100 %. But as said it up to the project manager to change according to scenarios .Ok now from the above function point estimation the estimation is 7 days let’s try to divide it across all phases.

Table   :- Phase wise effort distribution of man days

The above table shows the division of project man/days across project. Now let’s put

down the final quotation. Just a small comment about test cases.

Total number of Test Cases = (Function Point) raised to power of 1.2.This is as suggested

from caper Jones.

If you want to buy the project management book mail [email protected]  for more details or call any of our book shops MUMBAI-22078296/97/022-22070989, KOLKATA-22826518/19 HYDERABAD-24756967,24756400,BANGALORE-25587923, 25584641,AHMEDABAD-26421611,BHATINA(PUNJAB)-2237387,CHENNAI-28410796,28550491,DELHI/NEWDELHI-23254990/91,23325760,26415092,24691288.If you want to write to the author directly email at [email protected]
 

Home