Production Support Estimation Whitepaper

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Estimation of Production Support Projects White PaperVersion 1.0

Production Support White Paper

About this DocumentIt is very difficult to make a vigorous, plausible and job-risking defense of an estimate that is derived by no quantitative method, supported by little data and certified chiefly by the project managers guesstimates. At the same time, the conventional use of Function Point Analysis for Production Support projects is not possible in terms of both numerical size and implementation effort estimation since the support projects are primarily transaction based (i.e. ticket driven). Customized approach and guidelines are therefore necessary in order to estimate these projects.

This document gives an overview of the process of Estimation for Transaction Based Support Projects. The introduction deals with the steps of estimation in a broad spectrum and is followed by a dedicated section on the detailed steps of Estimation for Support projects.

PurposeThe intent of this document is to present an approach: a consistent methodology that can be used to measure the size, effort and FTE requirement of Production Support projects.

Intended AudienceProject Managers, Project Leads for Production Support projects.

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Production Support White Paper

Contents1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Problem to be Addressed .................................................................................................................................................................... 4 Production Support Projects An Overview................................................................................................................................ 4 Estimation Approach - Production Support Projects ................................................................................................................ 4 Estimation Process Flow for Production Support Projects...................................................................................................... 5 Size Estimation for Production Support Projects........................................................................................................................ 5 Effort Estimation...................................................................................................................................................................................... 6 FTE Determination ................................................................................................................................................................................. 8 Outstanding evidence of validity...................................................................................................................................................... 8 Take homes from this estimation model ....................................................................................................................................... 9

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Production Support White Paper

1.1

Problem to be Addressed

We are in an era where the significance of software estimation has been understood and efforts are channelized to build robust estimation frameworks. The majority of these efforts have been put into for developing estimation guidelines for Application development and Maintenance(ADM) projects. Time has come to address the estimation needs of other important areas of the IT industry.One such area would be the support projects, since the schedule for these projects is fixed in most of the cases, the neccessity of an estimation model has not been at the top of the agenda. An indepth analysis of the profitability of the support projects will show the vitality of estimations in profit margins. A fixed schedule does not ensure profit as it finally boils down to the effective resource employement which primarly depends on the estimates.This paper would bring in a dimensional shift in terms of estimation guidelines built in for IT industry as it addresses the estimation issues of one type of support project namely production support.

1.2

Production Support Projects An Overview

An application after being built is set in for production. The various stakeholders of the application need supports of different dimensions. The support activities could vary from creating users and it can go up to making minor changes in the application based on the requests raised by the users. Many a times the time frame for this kind of support is fixed by the customer . For example a project might be expected to provide support for 24*7 for five days a week for a period of three months.

1.3

Estimation Approach - Production Support Projects

Even prior to addressing how to estimate the question to be answered is what to estimate.The parameters to be estimated for a production support begins with the volume of work i.e size of the project. This paper considers the work volume to be performed as part of the production support projects in terms of the number of tickets/requests raised by the stake holders.Using the size value the effort for the project can be estimated. From effort the next parameter to be estimated will be the number of Full Time Equivalent i.e. the number of resources to be employed. As schedule for a project is fixed it is not considered for estimation. The estimation model presented in this paper is independent of the schedule as the the estimates derived from this model are for a week and this estimates are repeatable across weeks if there is no change in the work volume (i.e. no of tickets raised).

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Production Support White Paper

1.4

Estimation Process Flow for Production Support ProjectsThe approach for sizing Production Support projects can be explained through the diagram provided below. In this paper the ticket inflow is taken as the input for determining the size. Applying the productivity figure, we can then come up with the base effort. Additional effort contributing factors applicable for the project can then be applied on top of the base effort to get the resultant effort. This effort figure is then used to get the number of Full Time Equivalents (FTE)s required to support the job.

Start of Estimation

Collect Input Data for Project

Use some defect prediction model to determine the ticket inflow

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Tickets inflow Information Available?

YES

Estimate Size in Production Support Points

Ticket Distribution

Productivity determinator

Apply productivity to Estimate Base Effort Estimate Actual Effort Effort contributing factors

Estimate FTE Count

End of Estimation

Estimation Process Flow

1.5

Size Estimation for Production Support Projects

Production support jobs are primarily transaction based i.e. ticket based and mainly consists of the following typical activities Support given through email, over phone, changing data in the screen (e.g. granting privilege, password reset etc.) Providing work around solutions, data fixes Bug fixing, providing minor enhancement works Based on the work volume involved in each of these activities, the tickets can be categorized into various complexities (for example: Simple, Average, Complex). Normalization can be done for the different categories of tickets to derive the size of a production support engagement which can be represented in terms of Production Support Points (PSP). PSP calculated using Ticket Distribution hence indicates the normalized size derived from the ticket inflow i.e. the number of tickets to be handled by the project within a span of time5

Production Support White Paper

Note: In case the ticket distribution is not available, a distribution ratio can be assumed based on the historical data analysis from past project data for a particular organization.

1.6

Effort Estimation

OverviewThe effort for production support projects is calculated by applying productivity on the size calculated in terms of Production Support Points (PSP). In its simplest form, this relationship is expressed as: Effort = Size (PSP) / Productivity where Productivity is expressed as PSP / Person Months.

ProductivityThe generic definition of the term productivity is output per unit of input. In terms of estimation parameters it can be defined as size per unit effort. Productivity is the measure of effectiveness/efficiency. Productivity as a parameter provides a standard metric to compare performance between/within organizations. From estimation perspective productivity value enables effort estimation. If the unit of size is in PSP and the effort in terms of person hour (PH) then productivity would be PSP per unit of person hour.

Productivity DeterminationAnalysis of historical reveals that the key productivity determinators of a typical production support engagement are Application Platform Known Error Database (KEDB) No of Interfaces the application has 1. Platform SelectionProductivity

O ra cle Ap ps

Regression analysis of historical data shows that the productivity of a support engagement varies with the platform of the application being supported rather than the technology. Some of the possible platforms are Client Server, Mainframe/Legacy, Web based, ERP/Package, etc.

Productivity PSP/PM

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Production Support White Paper

2. The impact of Known Error Database (KEDB) on Productivity The productivity for a support job increases manifold with the presence of a strong Known Error Database (KEDB). Hence the base productivity needs to be adjusted depending on the impact of the KEDB present in a particular scenarioProductivity

Productivity Not Present

Mode