Spreadsheets and Business

Why the popularity of spreadsheets? “End user Computing” Long delays for IS department to do analysis and reports Ease-to-use, powerful software No need to wait for that overworked professional programmer Now - anyone can write software to do business analyses

There’s the Rub……. Critical business analyses is being done by amateurs Think about …. How dependent business is on spreadsheets and How little validity checking is actually done! James A. Cummings, Inc >>>

Criteria for good spreadsheet design Accuracy –testing –Data entry controls to limit errors Clarity –Easily understood by creator other users Flexibility –Easily adapted –Remains valid

Conceptual Model for Worksheet Layout Input - Process - Output Clearly separate Input from Output Clearly specify Assumptions To be more specific …………………...

Desirable to have separate areas for: Identification Area Input Area Assumptions / Definitions / Formulas Work Area Output Area Macros (may not have them all in every sheet.) AMORT_TABLE.XLS >>

Tips Break lengthy formulas into parts –Easily hidden later Use Functions Rather than Formulas Use Labels, Shading, Lines, Color –anything to enhance readability But don’t confuse –Form over Function –Aesthetics over Accuracy Cummings (2) >>>

Tips Clearly specify units of measure No Numbers In Formulas –All placed in separate cells and referenced Annotate Often Document (i.e. Write It Down) –Assumptions –Formulas No_5 template >>>>>

Tips Get familiar with the Auditing Toolbar –precedents –dependents –Trace Error Auditing Toolbar >>>>>

Testing Accuracy of Worksheet –test with simple and predictable data Full range of values Independent Verification –Another set of eyes –A known test problem Ad Hoc Testing - Whenever using a spreadsheet –The ‘eyeball’ test