Management Paper – Commercial Spreadsheet Review Simon Murphy [email protected] Developer...
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Transcript of Management Paper – Commercial Spreadsheet Review Simon Murphy [email protected] Developer...
Spreadsheet background• Up to 200 Mb size• Up to 1 Million formulas• 1-10,000 unique formulas• 5-10,000 lines of VBA• £1M to 100’s of Billions in values• Often linked to other technologies
such as OLAP, ADO, COM or .net etc.• Finance, Banking and Sales and
Marketing areas
Agenda• Introduction• Scope of Review• Stages of Review
– Spreadsheet in context– File Review– Workbook Review– Sheet Summary– Inter Sheet Interactions– Cell/Block level Relationships
• Summary• Conclusion• Any Questions?
Introduction - Spreadsheet Quote
Program Manager to Steering Committee:
“We can build this system in – a large consolidation software package –, it will take 2 developers 6 months and cost half a million. Or 1 developer can do it in Excel in 10 weeks for 30 thousand.”
Introduction - Spreadsheet Definition
• 2006 - Organisational
–Spreadsheet – the product of one or more people following some sort of process to a deadline.
• 2005 - Technical
– Spreadsheet – powerful and flexible, single end user, analysis and presentation tool, optimised for speed of initial development.
Scope of Review• The review is pre-sales (i.e. ‘free’)• The aim of the review is to estimate
the time to repair, enhance, or migrate the spreadsheet.
• Totally NOT any sort of audit.• Target time is 2-4 hours.• Explicit assumption the spreadsheet
is fit for purpose currently.• Assumes no useful documentation.
Spreadsheet in Context• What is it used for?• How important is it?• How connected is it?• Is network access required?
Sheet Summary• Once sentence summary (if possible) of
what the sheet does.• Added to navigation sheet
Inter Sheet Interactions
• Data flows• Left hand are pure children/source sheets• Right hand side are unconnected (by basic formulas)
Cell/Block level Relationships• Review the actual formulas for shapes
• Finally work though a few formulas
Some Fun Formulas1. =IF(AND(AND(AND(AND('s29'!AK50=0,'s29'!
AK51=0,'s29'!AK54=0,'s29'!AK55=0)))),"N","")2. =IF(AND($E$45="a",AF9>0),AK45,IF($E$45="M"
,AK45/12*$E$9/30,IF(AND($E$45="Q",AF9>0),IF(AK50=12,AK45/4,IF(AK50=11,AK45*3/11,IF(AK50=10,AK45*2/10,0))),AK45*0)))
3. =IF(AND(I89<>0,I88=0,SUM($U$88:U88)=0),1,IF(OR(ISERROR(I89),NOT(ISNUMBER(I89))),"Error",0))
4. =+B49*(0.173076923076923)5. =+E27*SUM(D5/G5)6. =SUM('PayEx'!$U5*'PayEx (Annual) '!
$J$5)*(100%+'% Increase in x'!CH7)7. =G43*1000/G83
Last one• =E111+E118+E119+E120+E121+E
122+E123+E124+E125+E185+E186+E187+E188+E189+E190+E191+E216+E217+E218+E219+E220+E222+E223+E227+E233+E234+E240+E241+E246+E468+E469+E470+E471+E472+E475+E533+E534+E535+E536+E537+E540+E579+E580+E581-E257-E252
Summary• Brief overview of one commercial
review process• Aim to drill into a spreadsheet one
level at a time• Target is to make changes to a live
spreadsheet without introducing new errors
Conclusion• Using a few basic tools and a
structured approach it is possible to gain a reasonable understanding of a spreadsheet within commercially viable timescales.
Questions?
• [email protected]– Spreadsheet consulting, reviewing,
maintaining, rescuing, migrating, add-in development etc.
• Websites– www.codematic.net– www.xlanalyst.co.uk