A Visual Answer to ‘What if ‘ Questions
Since the first electronic spreadsheet, VisiCalc, was introduced for the early Apple computer, all spreadsheets have been designed around the same fundamental grid of rectangular cells formed by the intersections of columns and rows. But not anymore.
DS Group Inc. of Greenwich, Conn., ((800) 828-8760) is direct-marketing an Italian-designed spreadsheet that doesn’t have the traditional cells housing labels, data and formulas.
DS Lab ($195) is called a “visual spreadsheet,” and, in fact, it displays data models in diagram fashion. The closest analogy would be a flow chart. (If you want to try it out, a full working version of the program, with limited modeling capacity, is available for $9.95 from the publisher.)
The idea behind DS Lab is to overcome two of the shortcomings of traditional spreadsheet programs:
* Formulas are often hard to decipher.
* Time sequences are too difficult to handle.
What DS Lab provides is a Windows program for IBM and compatible PCs that is designed to model complex “what if” scenarios, particularly those involving time sequences. For instance, the program’s tutorial models cumulative net profit monthly over a year. Another example determines which telephone service is least expensive based on various assumptions about the type and number of calls being placed.
According to Sergio Mazza, DS Group’s president, the company used DS Lab to compare the cost of various employee health plans, testing different assumptions about employee health over the life of the plans.
All of those tasks can be done with a traditional spreadsheet, but they are done quicker and easier with DS Lab.
The program is intended as an adjunct to traditional spreadsheet software rather than as a replacement. In fact, it is designed to link directly with Microsoft Excel for storing and graphing the results of running a scenario. The table of results can also be used in other spreadsheets or in a word processing document, but you have to use cut-and-paste to get it there.
Frankly, when you first load up one of the sample files on your computer screen, it looks confusing. Not until I had built my own model following the tutorial chapter in the manual did all the geometric symbols and connecting arrows on the screen make sense. Then, not only could I understand what I was looking at, but the program was fun to use and even appealed to my aesthetic sense as I nudged elements around on the screen to group them in a more pleasing way.
Where the building block of a spreadsheet is the cell, in DS Lab it is a symbol called an “element.”
The elements are various pre-drawn shapes--selected either from a tool bar at the top of the screen or a pull-down menu--that represent data types. Variables are shown as circles and constants as squares. There also are symbols for a numerical series, such as closing stock prices over a month, and for “inputs,” which are where you enter values to start a simulation. A series can actually be a table of 100 rows by 16 columns of numbers.
Thus, the limit in DS Lab of 100 elements times 365 steps is more than adequate for all but the most complex models. For those, there is DS Lab Pro ($995), with room for 1,000 elements and 2,048 steps.
On the screen, lines with arrowheads connect one element to another to identify their relationship. For instance, the arrows might show that a variable named Gross Sales was linked both to a constant called Unit Price and a variable called Items Sold. That is easier to understand than the traditional spreadsheet method of referring to such values by cell intersection names such as B3 or D22.
Even though, with a little extra work, you can give names to important cells in today’s leading spreadsheets, it’s a little harder to place them diagrammatically to illustrate their relationships, which DS Lab does naturally.
Once you place and connect all the elements of a scenario, you are ready to define the formulas that affect them. The program gives you a lot of help as you build a formula in a “dialogue box” that pops up on the screen. Not only does it already contain the names of related elements (because of the links you have drawn), it contains the names of all the mathematical functions in the program. You merely pick the appropriate function from the list.
As you build the what-if scenario, you decide how many variations should be tested and at what intervals. For instance, a net profit model could be run monthly or quarterly or yearly.
The program gives you excellent command over time intervals. Its built-in functions are strong in financial transactions, and there are also inventory, statistical and the typical mathematical functions.
The screen quickly fills with elements and their connecting arrows, but various “zoom” levels let you see as much or as little of the whole picture as you want. The program also automatically divides your model into pages equivalent to the size of paper in your printer. You can reduce a large model onto a single sheet to make an overhead transparency, or you can print it full-size on as many sheets of paper as necessary and then tape them together mosaic-fashion to create a poster-size rendition of the model.
If you do a lot of what-if modeling, especially over time intervals, and you’ve been wishing there was an easier way to do it, DS Lab or DS Lab Pro may be the tool you’ve hoped for.
