Software Measurement and Function Point Metrics

Software Measurement and Function

Point metrics in a broad software

contractual agreement

Roberto Meli – Tommaso Iorio

Roma 16-17-18 Marzo 2005

Different types of pricing approaches:

dis/advantages

‡

Total Fixed Cost for Specified Product (also

called Turnkey Supply),

‡

Total Variable Cost for Time & Material

‡

Total Variable Cost for Released Product based

on unitary fixed costs

Fixed Price Function Point: Problem

‡ no manager can accept to be penalized on his/her

project while other projects are valued for the profitability provided to the overall program…

‡ due to the desired uncertainty of the open contract in

terms of requirements (what, how, when and how much) needed to maximize flexibility of the

outsourcing choice, there is no guarantee that the final mix of actual required projects is exactly the one on which the productivity average has been

estimated …

‡ FP calculated as backfiring from costs or other

What is the right price-fixing model, then, to be

applied to general contracts and open

contract? And more, what is the workflow

that, based on the supplier-customer

interaction, leads to the right price?

Price evaluation: a transactional issue

Customer Supplier Requirements Solution(TCQ2₎ Negotiation Contract Market Transactions Market Transactions External Productivity Internal Productivity Internal Productivity Constraints Requirements Constraints Quantity Quality Effort Time Staff Unitarystaff cost Discount Total cost

use of a (transparent) methodological

model in a contract: advantages

‡ data and price-fixing mechanisms

can be shared between the parties of the contract

‡ by using the model, the

“haggling” tends to shift away from the price and more on the key factors that enhances price accountability

‡ the model gives the opportunity

to use the embedded know-how even to beginners.

Customer Supplier

Suggested solution

‡

A model (1) to objectively measure the

software supply, in terms of

the value

perceived by the Customer

(measured in terms of “

price

”)

‡

A model (2) to estimate the software supply

cost incurred by the Supplier

Methodological reference context

‡ The model complies with ISO 14143 international

standards (FSM Definition of concepts) and transposed by IFPUG into the White Paper: Framework for

Functional Sizing issue 1.0 -Sept. 2003)

‡ The model is based upon the most objective metrics

correlated with experimental data and is predicated upon a thorough evaluation of key project factors,

‡ The model applies mainly to large software projects

involving new developments and enhancements, where efforts and costs are mainly driven by the

functional size, as shown by benchmarking statistics, such as ISBSG database statistics.

Our methodological reference context

exclude

‡

Activities with no functional impacts:

| Feasibility Studies ;

| Application Porting

| MAC (corrective maintenance )

| Application Installation or deployment ;

| System activities;

| …

Next slides…

‡

Model (1): from Requirements to Price

‡Model’s description

‡Workflow description

‡

Model (2): from Requirements to Cost

‡Model’s description (cenni)

Step of Model to determine Price

1. Measurement of released and worked functionalities

(IFPUG UFP and/or Early & Quick Function Point)

2. For each adjustment factor evaluation of impact level (for

example very low, low, normal, high, very high, extremely high), and calculating the total adjustment factor (TAF) through the multiplication of all values

3. Computation of the Business Function Point

(BFP = WFP x TAF )

What is the

Unitary Average Price for a BFP ?

‡

It is simply the Unitary Average Market Price

of a Standard Unadjusted Function Point

when:

| No reuse or replication is made

and

| Average (market) application complexity

| Average (market) technical and quality factors

| Average (market) productivity factors

Model 1: the workflow 1/3

Set the Model

Quantitative definition of Technical and Quality Factors Quantitative definition of Productivity Factors Table to be shared with Suppliers • “una-tantum” at start-up

• the factors can be selected/quantified by internal analysis (for example Delphi method) and/or referring other cost models (for example Cocomo)

Model 1: the workflow 2/3

Set the Contract

Functional Requirements Definition Non Functional Requirements evaluation of impact level for each factors

Feasibility Study /

Request For Proposal /

… • Step for each Project/Contract

• Set the impact level for each factors, based up on characteristics of Customer

Model 1: the workflow 3/3

Contract Governance

Supplier Estimate BFP SW realization BFP measures Customer Estimation Approval Measurements Approvals Invoicing

“Requirement to Cost” cycle

MISURA FP_FP DETERMINAZIONE WFPWFP

Complessit

Complessitàà _{replicazionereplicazione}Riuso e Riuso e

CALCOLO

MEASURE FPFP DETERMINE WFPWFP

Complexity Reuse and Replication

REQUIREMENTS ESTIMATE CALCULATE COST ISBSG ISBSG DB aziendale ISBSG ISBSG Impegno Impegno medio

medioMost Likely_Effort

CALCULATE Adjusted Effort Costo Orario Costo Orario Ciclo di Vita Ciclo di Vita Risorse Risorse

Fattori Tecnici e di Qualit

Fattori Tecnici e di Qualitàà Fattori di Produttivit Fattori di Produttivitàà aziendali aziendali Hour Cost SW Life Cycle Resources Company

Technicals and Quality Factors

Company Productivity Factors

Total Adjustment Factor

MISURA FPFP DETERMINAZIONE WFPWFP

Complessit

Complessitàà _{replicazionereplicazione}Riuso e Riuso e

CALCOLO

MEASURE FPFP DETERMINE WFPWFP

Complexity Reuse and Replication

REQUIREMENTS REQUIREMENTS ESTIMATE ESTIMATE CALCULATE CALCULATE COST COST ISBSG ISBSG DB aziendale ISBSG ISBSGISBSG ISBSG DB aziendale ISBSG ISBSG Impegno Impegno medio

medioMost LikelyMost Likely_EffortEffort

CALCULATE CALCULATE Adjusted Effort Adjusted Effort Costo Orario Costo Orario Ciclo di Vita Ciclo di Vita Risorse Risorse

Fattori Tecnici e di Qualit

Fattori Tecnici e di Qualitàà Fattori di Produttivit Fattori di Produttivitàà aziendali aziendali Hour Cost SW Life Cycle Resources Company

Technicals and Quality Factors

Company

Technicals and Quality Factors

Company Productivity Factors

Company Productivity Factors

Total Adjustment Factor Total Adjustment Factor

Step of Model to determine Cost

1. Measurement of released and worked functionalities (IFPUG UFP and/or Early & Quick Function Point)

2. Definition of the features dealing with:

1. Technical and Qualitative dimension (Technical Adjustment Factors)

2. Business Productivity (Productivity Factors)

3. Estimation of managerial variables (most likely effort and

duration)

4. Most likely effort is weighted up against business

parameters

Suggestions from past experiences

‡

How to select and evaluate Adjustment

Factors

‡

Relationship between adjustment and risk

factors

‡

Estimating and measuring effectively

Ongoing Change Requests

Conclusions

‡

Two different points of view, two models:

to determine price and to determine cost…

‡

It is possible to integrate the models…

‡

Worked and Business Function Points to

overcome the limits and problems of

“Function Point fixed-price …