Gathering Business Requirements for Data Warehouses

© 2010 Data Management & Warehousing © 2010 Data Management & Warehousing

Gathering Business Requirements An overview of the Data Management & Warehousing approach

21 Jan 2010 Gathering Business Requirements © 2010 Data Management & Warehousing

© 2010 Data Management & Warehousing

Agenda

¤  Overview of the process ¤  Why gather requirements like this? ¤  Types of requirement ¤  Understanding what we can do ¤  Business processes create data ¤  Understanding dimensions and measures ¤  How these requirements are used ¤  Things to remember

¤  Straw-man Proposal ¤  A "straw-man proposal" is a simple proposal intended to

generate discussion of its disadvantages and to provoke the generation of new and better proposals.

¤  Next Steps

21 Jan 2010 Gathering Business Requirements


Overview of the process

Why gather requirements like this?

Types of requirement

Understanding what we can do

Business processes create data

Understanding dimensions and measures

How these requirements are used

Things to remember



Why gather requirements like this?

¤  Your opportunity to explain to us what you want to see from the system in a way that we can understand

¤  There are two parts to this: ¤  US: Ensuring that you get the information that you need to

run the business effectively ¤  YOU: Ensuring that we understand enough about what you

want to quickly and effectively deliver that information

¤  Success requires effective two way communication

¤  Requirements always change ¤  Don’t worry – we know that things will be forgotten or

change – but once we have a good baseline it is much easier to refine and enhance the solution

¤  We will address how to update the requirements later



Types of requirements

¤  There are two types of requirement we need: ¤  Business Requirements

¤  What information do you want to see? (the data and how it needs to be grouped) This is the primary focus of the workshop

¤  Technical Requirements

¤  When do you want to see the information (Frequency of refresh and of reporting)

¤  How do you want the information formatted? (Tables, graphs, charts, etc.)

¤  Where do you want to see it? (Web, e-mail, RSS, application, etc.)

¤  Who should see the information? (Security, publication)



Understanding what we can do

¤  We can only deliver data that is there ¤  We capture as much as we can at the lowest level to use

but your environment creates limitations ¤  This is true of every organisation

¤  We have to prioritise which data we deal with ¤  Whilst we try to deliver as much as possible as quickly as

possible we have to ensure that the most important things are delivered first

¤  We can only optimise what you ask us to optimise ¤  Business intelligence solutions group and aggregate data

to optimise it for reporting and presentation ¤  Whilst we will have all the data that is available it may take

time to make it available if we don’t know that it is required as a priority for reporting



Example Limitations

¤  We only get a feed once a day from the source ¤  LIMITATION: Data can only be refreshed daily

¤  We only get source data in x units ¤  LIMITATION: Limits the granularity of the reports (e.g. if the data is

number of calls per hour, we can not report calls per minute)

¤  The source data has data type discrepancies ¤  LIMITATION: Over time this will negatively affect data quality (e.g. if

31st Feb consistently appears it how do we handle the data?)

¤  We only get a subset of data from source system ¤  LIMITATION: If we haven’t asked for it we won’t get it ¤  LIMITATION: We may not be able to go back and get historical

information if we change the subset of data

¤  None of these are show stoppers, all can be changed as long as we know what we need



Business processes create data

¤  There is a known state - a checkpoint ¤  This is measurable using a set of criteria known as dimensions

¤  Some process step is performed – a flow

¤  There is now a new known state - another checkpoint ¤  This is also measurable ¤  Some of the dimensions will have remained the same ¤  But some dimensions will be added and some removed

¤  Reporting is the delivery of data for a given state or states ¤  Reports should be designed to inform management decision making

¤  Analysis is the attempt to gain understanding of the causes of the state change ¤  Analysis should be designed to help improve the business process

¤  You must have the reporting data before you can effectively perform analysis



Understanding Dimensions

Levels Hierarchy Values and Descriptions

Filters: Level = Value e.g. Month = ‘December 2010’


¤  Typical Dimensions might include:

¤  Calendar

¤  Geography

¤  Customer

¤  Channel

¤  Product

¤  Partner

¤  Manufacturer

¤  Discount Type


Understanding Measures

¤  Numeric Values ¤  Examples: Quantities, Money, Time ¤  Basic Maths: Sum, Count, Maximum, Minimum ¤  Derived Maths: Average, StdDev, Rank

¤  Linked to and described by Dimensions ¤  Every measure relates to many dimensions ¤  Always relates to the lowest possible level of each

hierarchy

¤  Example: ¤  Number (Measure) and Value (Measure) of

Product (Dimension) sold on Date (Dimension) through Channel (Dimension)



How these requirements are used …


Select Month County

Descriptions

Count(Policy) Sum(Premium)

Basic Maths On Numeric Values

Average(Premium) Rank(Policy)

Derived Maths On Numeric Values

From Policies Measures

Calendar Geography

Dimensions

Where And

Year = ‘2010’ Country = ‘England’

Filters

Group By Month County

Levels

Order By Rank(Policy) Sorting

And And

Policy Date = Calendar Date Policy Postcode = Geography Postcode

Joins


… to produce a report …


Month County Count(Policy) Sum(Premium) Average(Premium) Rank(Policy) Jan-2010 Portsmouth 4,956 200,000.00 £40.36 1 Jan-2010 Greater London 4,851 7,611,900.00 £1,569.14 2 Jan-2010 Southampton 4,707 234,600.00 £49.84 3 Jan-2010 Luton 4,424 191,800.00 £43.35 4 Jan-2010 Blackpool 4,064 141,900.00 £34.92 5 Jan-2010 Leicester 4,020 294,700.00 £73.31 6 Jan-2010 Southend-on-Sea 3,935 164,300.00 £41.75 7 Jan-2010 Nottingham 3,919 292,400.00 £74.61 8 Jan-2010 Bristol 3,844 421,300.00 £109.60 9 Jan-2010 Slough 3,724 121,200.00 £32.55 10 Jan-2010 Hull 3,621 258,700.00 £71.44 11 Jan-2010 Reading 3,607 145,700.00 £40.39 12 Jan-2010 Bournemouth 3,549 163,900.00 £46.18 13 Jan-2010 Plymouth 3,169 252,800.00 £79.77 14 Jan-2010 Brighton & Hove 3,104 256,600.00 £82.67 15 Jan-2010 Derby 3,065 239,200.00 £78.04 16 Jan-2010 West Midlands 2,905 2,619,500.00 £901.72 17 Jan-2010 Middlesbrough 2,580 139,000.00 £53.88 18 Jan-2010 Stoke-on-Trent 2,569 240,100.00 £93.46 19 Jan-2010 Poole 2,144 138,800.00 £64.74 20 Jan-2010 Torbay 2,131 134,000.00 £62.88 21 Jan-2010 Merseyside 2,090 1,347,800.00 £644.88 22 Jan-2010 Tyne and Wear 2,025 1,093,400.00 £539.95 23 Jan-2010 Greater Manchester 2,017 2,573,500.00 £1,275.90 24 Jan-2010 Halton 1,515 119,800.00 £79.08 25 Jan-2010 Medway 1,320 253,500.00 £192.05 26 Jan-2010 Warrington 1,086 196,200.00 £180.66 27 Jan-2010 West Yorkshire 1,084 2,200,500.00 £2,029.98 28 Jan-2010 Bracknell Forest 1,049 114,700.00 £109.34 29 Jan-2010 Blackburn with Darwen 1,027 140,700.00 £137.00 30


… or to produce a chart


£0.00 £500.00

£1,000.00 £1,500.00 £2,000.00 £2,500.00 £3,000.00 £3,500.00 £4,000.00 £4,500.00 £5,000.00

Average(Premium)

Count(Policy)


Insurance Example CHECKPOINT CHECKPOINT FLOW

REPORTING The quantity and value of quotes by: • Quote Date • Proposed Start Date • Channel • Personal Data

REPORTING The quantity and value of policies by: • Policy Start/End Date • Channel • Personal Data

ANALYSIS Why do people convert? • What are the common characteristics • What are the differences



More checkpoints … Anonymous quotes provided to aggregator

Anonymous quotes provided to website

Known quotes provided to website

Quote conversion to policy

¤  At each subsequent checkpoint we typically get:

¤  More dimensions – more information to qualify the data

¤  Less transactional data – less individual transactions involved


Flow

Flow

Flow


Things to remember …

¤  Keep your requirements ‘reasonable’ ¤  Can be sourced from existing source systems ¤  Will be used to affect your decision making ¤  Consider things in terms of ‘MoSCoW’:

Must Have; Should Have; Could Have; Would Have ¤  Focus your time and effort on Must and Should Haves

¤  Expect to be challenged by us ¤  This is just to make sure that we understand everything by

getting you to (re-)explain and justify

¤  You are the experts in your business ... ¤  We know how manage data to deliver business

intelligence ¤  We know more than most about how data works

¤  See http://datamgmt.com/how-data-works ¤  Working together we can specify the optimal solution



Straw-man Proposal

A "straw-man proposal" is a simple proposal intended to generate discussion of its disadvantages and to provoke the generation of new and better proposals. Often, a straw man document will be

prepared by one or two people prior to kicking off a larger project. In this way, the team can jump start their discussions with a

document that is likely to contain many, but not all the key aspects to be discussed.



Sources for Straw-man Sources for the straw-man:

Other potential data sources:



Straw-man Description

Measures Analyse by



Next Steps …

Do we need more time to add more requirements?

How will we review the requirements?

Who will help flesh out the technical requirements?

Who will sign off the requirements?

Any other questions?



Simply Explained …


Geek & Poke http://geekandpoke.typepad.com


How we record requirements



Understanding the requirements gap


The difference between what was required when the development started and what is required when the development is delivered

Overcome by: a) accepting and embracing it b) ccommunicating with users so everyone understands the time lag c) delivering in fast, small increments


Thank You


Documents

Gathering Business Requirements for Data Warehouses