HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Guest Blogs

Don’t Risk Your Most Important Calculations to Spreadsheets

NO RATINGS
View Comments: Oldest First|Newest First|Threaded View
Page 1/3  >  >>
williamlweaver
User Rank
Platinum
Conclusion Obvious?
williamlweaver   3/15/2013 8:08:00 AM
NO RATINGS
Thanks for the study, Brent. Was this an Hypothesis-Driven study or a Data-Driven study? I'm a scientist, not an engineer, but I do use spreadsheet calculations to do quick statistics on very small collections of preliminary data. To analyze experimental results I go a bit deeper and use either MathCAD or Mathematica depending on the preference of my collaborators. For measurements and signal processing I use test-driven software development guidelines to produce code in National Instruments LabVIEW. I use a spreadsheet to document quick calculations that I used to perform with a handheld calculator.

I would hypothesize the use of spreadsheets to analyze mission-critical data would be widespread in business and financial applications. Is it that widespread in science and engineering?

tekochip
User Rank
Platinum
Test Data
tekochip   3/15/2013 9:31:25 AM
NO RATINGS
You have to keep in mind that creating a spreadsheet is much like a creating a software program.  You wouldn't trust a program without running test data through it, and you really have to do the same with a spreadsheet.


Pubudu
User Rank
Platinum
Re: Test Data
Pubudu   3/15/2013 2:00:44 PM
NO RATINGS
Thank you very much for the very informative article, actually I have some bad experience with spreadsheets, But my mind did not like to believe that it is with the spreadsheets fault always in my side. Now I know what has gone wrong. 

Pubudu
User Rank
Platinum
Re: Test Data
Pubudu   3/15/2013 2:05:05 PM
NO RATINGS
Tekochip yes I also with you but my problem is when we changed the data sometimes sum functions has changed without knowing me. Is there a any method of locking the formulas after checking the test data. 

Charles Murray
User Rank
Blogger
91% error rate
Charles Murray   3/15/2013 5:54:01 PM
NO RATINGS
Ninety-one percent of spreadsheets contain errors? The nice thing about handheld calculators (and sliderules before that) was that the engineer was more connected to the calculation. There's a subtle disconnect when doing the calculation in software on a spreadsheet, which makes it easier for a resulting number to gain a couple of zeroes and still not be noticed.

Pubudu
User Rank
Platinum
Re: 91% error rate
Pubudu   3/16/2013 2:57:38 AM
NO RATINGS
Charles normally we always depend on the spreadsheets, If it is contain 91% errors what will be the best option to overcome this issue. 

TJ McDermott
User Rank
Blogger
Re: 91% error rate
TJ McDermott   3/17/2013 2:22:50 PM
NO RATINGS
Charles, one could as easily say 91% of hammer-driven nails are bent.  The thrust of that statement would be powder-gun or electric-gun driven nails go in straight.

91% of nails may be bent by hammer-wielders, but that doesn't mean they don't hold just as well as the gun driven ones.

 

TJ McDermott
User Rank
Blogger
One has to question the source
TJ McDermott   3/17/2013 2:36:44 PM
NO RATINGS
The author of the blog references a book by Chad Jackson and thoughtfully provides a link to it.

According to https://twitter.com/ChadKJackson, Mr. Jackson is the president and principal analyst of Lifecycle Insights.

Lifecycle Interests refers to the same e-book at this link: http://www.lifecycleinsights.com/solving-engineerings-calculation-compromise-ebook/

However, Lifecycle Interests does not seem to host the e-book on its own website.  The book instead is hosted at the web site of this blog's author, PTC.  The author's company does not host its own work?

One has to question the source for the conclusions of the blog (and by inference the book as well).

I don't necessarily disagree that spreadsheets can cause errors to propagate because they tend to hide the equations.  It does not negate their incredible usefulness.  Other commenters have already noted the need for testing and checking.  ANY tool needs that.  The software being pushed by the blog author needs it just as much.  It may make the process simpler, and add some helping hand, but it also needs to be checked.

 

ab3a
User Rank
Platinum
Advice from my mentors
ab3a   3/18/2013 9:25:33 AM
NO RATINGS
Years ago, when slide rules were still found in desks and calculators roamed the earth, my mentors gave me this advice:

"If you find that you can't do your initial estimates with a basic scientific calculator, STOP. If you find yourself digging out your textbooks and writing equations, STOP. --You are probably about to make a huge mistake.

"Someone before you has probably seen this problem and has an acceptable plant equation or rule of thumb that you can use. If you reinvent that wheel, the chance that you will make a mistake is very high. You should use those text books to validate or invalidate an approach, not to create new ones, unless the old approaches are clearly inadequate somehow and you are really treading on new territory."

And in the years since, I have used those textbooks to create new approaches, but only in a handful of cases.

The point about spreadsheets is much the same: If someone has written and validated software, USE IT. The chances of making a mistake when modeling with a generic tool such as a spreadsheet or writing your own modeling software are VERY high.

As engineers we have an obligation to our employers, clients, and to the public to get the correct answers. If there is prior art that you can use to help you in this process, USE IT.

 

Jake Brodsky

Droid
User Rank
Platinum
At least you can see the formulas
Droid   3/18/2013 10:06:30 AM
NO RATINGS
There is a skeptical side of most engineers that demands to verify everything and assume very little. Last time I checked - (unless the spreadsheet is locked) formulas are easily visible and we can see how values are being calculated.  I prefer that scenario over feeding values into a software "black box", shaking it a bit and then accepting the answer.

Page 1/3  >  >>
Partner Zone
More Blogs from Guest Blogs
As additive manufacturing (including 3D printing) becomes increasingly popular among businesses as a quick and easy solution to creating and evaluating prototypes and end-use products, the debate about whether to outsource production or to purchase equipment for in-house use is at the forefront of industry discussions.
With increasing terrorist threats overseas, organizations are thinking about how best to defend themselves here and abroad. Engineering can play a role, especially when it comes to putting a barrier between yourself and the bad guys.
Time to market is everything, but at the same time, you can’t sacrifice quality for speed. That’s where additive manufacturing comes into play.
In the last few years, use of CFD in building design has increased manifolds. Computational fluid dynamics is effective in analyzing the flow and thermal properties of air within spaces. It can be used in buildings to find the best measures for comfortable temperature at low energy use.
Feature-advantage-benefit could help engineers in how we approach design problems, how we sell our ideas to management, and how we market ourselves when it comes to jobs.
Design News Webinar Series
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: 10/28-10/30 11:00 AM
Sponsored by Stratasys
Next Class: 10/28-10/30 2:00 PM
Sponsored by Gates Corporation
Next Class: 11/11-11/13 2:00 PM
Sponsored by Littelfuse
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service