Std-11Version 1.0

Tuffley Computer Services

Quality Management System

Std-11

Project estimating

Version: / 0.1
Date: / 3/3/09
Status: / Draft
Copy no.: / Uncontrolled
Approved by:

QMSProject Estimating1

Std-11Version 1.0

Preface

For more information on this standard, contact David Tuffley,

This document was saved in MS Word for Vista.

Revision History

Date / Ver. / Author / Comments
1/5/95 / 0.1 / D. Tuffley / Create standard
14/7/09 / 1.0 / D. Tuffley / Finalise

Copyright  Tuffley Computer Services, 1995-2009. This publication is copyright and contains information which is the property of Tuffley Computer Services. No part of this document may be copied or stored in a retrieval system without the written permission of the Director, Tuffley Computer Services.

QMSProject Estimating1

Std-11Version 1.0

Contents

1.Introduction

1.1.Scope

1.2.Objectives

1.3.References & sources

1.4.Definitions & acronyms

1.5.Responsibilities

2.Standard / procedure description

2.1.Introduction

2.2.Estimating procedure

1.Introduction

The estimating standard outlines the general procedure by which project staff develops realistic estimates of the time and resources needed to complete a project within the specified timeframe.

1.1.Scope

The scope of this standard is to provide estimating guidelines to project management. It does not prescribe any estimating methodologies - the choice of which is at the discretion of the project manager. Neither does it cover cost/benefit analysis.

1.2.Objectives

The objective of this standard is to provide project management with general guidelines concerning the estimating process. These guidelines allow the estimation of the person hours required to accomplish the block of work.

1.3.References & sources

[1]IEEE 1298 -1987
Standard for Software Quality Management Systems
IEEE Software Engineering Standards 1993 Ed.

[2]AS 3563
Software Quality management System
Standards Australia, 1994

[3]AS 3901
Quality systems for quality assurance in
design/development, production, installation
and servicing.
Standards Australia, 1994

[4]ISO 9001 Quality systems - model for quality
assurance in design/development, production,
installation and servicing.
Standards Australia, 1994

1.4.Definitions & acronyms

Actual / The actual time taken to accomplish a particular activity or piece of work.
Estimate / A prediction, based on historical evidence and/or experience, that is equally likely to be above or below the actual result.
Metric / A measurable indication of some quantitative aspect of a system eg size, cost, risk, elapsed time etc.
Work Plan / A list of the activities to be performed to complete a particular piece of work.

1.5.Responsibilities

The Project Manager is responsible for producing realistic, documented and repeatable estimates.

2.Standard / procedure description

2.1.Introduction

The project manager may use any valid estimating method, according to his or her preference. Whichever method is used must however be documented.

Estimates shall be made at the following times.

  • The beginning of a project.
  • The beginning of each new phase of the project.
  • Following any major change of project scope.

The work plan for the project specifies the estimating activities needed for a particular project. Estimates are often used to set performance goals.

When estimates have been made based on generic statements of required and available skills, the estimates should be reevaluated when the particular skills of the allocated resources are known.

Three estimates shall be made, as follows.

  • Best case - the hours required if everything goes very well - better than expected.
  • Likely - the hours required if everything goes as expected (i.e. a realistic scenario).
  • Worst case - the hours required if 'everything goes wrong'.

The objective is to produce estimates of the person hours needed to accomplish the block of work, and to document the method, assumptions and calculations used to determine that figure.

These documents are useful when reestimating a project or for historical evidence of the accuracy of different methods of estimation.

It's important to record actual hours spent on each project activity so that Estimates vs Actuals can be plotted. Other factors that have been used to create the estimate (i.e. number of functions or users etc) should also collected as an 'actual' figure.

The person hours estimates help determine the following.

  • Resources and costs associated with the project.
  • Duration and delivery dates for the project.

Base estimates wherever possible on past actual performance and/or experience. Use proven algorithms rather than optimistic, best case predictions. The aim of estimation is to produce a 'likely' estimate that is as close as possible to the final actual figure.

2.2.Estimating procedure

Regardless of which estimating methodology is used, the following general guidelines must be applied.

  1. Collect reference material - ensure that all the relevant information has been collected, such as the terms of reference for the project.
  2. Compare previous projects - research the histories of other similar projects, noting the details of the effort required and other factors regarding size etc.
  3. Decide on estimating method - determine the estimation method most appropriate to this project
  4. Calculate estimate - derive the project estimate using the selected methodology. Make certain that the following are recorded on the estimation work sheet.
  • Principles of the technique used.
  • Assumptions made.
  • Calculations performed.
  1. Contingencies - ensure that the estimate allows for the following.
  • Training.
  • Meetings.
  • Project management tasks.
  • Project reviews & audits.
  1. Issues - document any issues arising from the estimating process.
  2. Alternative technique - where the estimate is greater than 2000 hours (i.e. around 1 person year), do a second estimate using an alternative technique.
  3. Compare estimates - if a second estimate has been prepared, discuss any differences between the estimates and arrive at a consensus. Document this.
  4. Project file - since they are quality records, file the project estimates and the supporting documentation in the project file.

QMSProject Estimating1