Here is a (somewhat long) recipe for batch processing a model that was initially intended for one case only.
It was written by me and than substantially improved by Mike Fay
--
Kind regards,
Niek Otten
Microsoft MVP - Excel
===========Article by Excel MVP Niek Otten=====================
Easily extend a complex Excel model for one set of input/outputs, to many sets of input/output
Sometimes you want to apply an existing worksheet calculation to many sets of data rather than just the one case for which it was
designed. For example, you developed a worksheet which calculates your pension. It accepts some twenty input variables and
generates five output variables. Then your boss demands that you apply that one-time worksheet to 500 employees. (Holds up fist...
boss!?!)
Of course you could write some VBA code to do this. But many people hesitate to use VBA and often they are not even allowed to, on
their work PC. Fortunately, there is a solution that does not require VBA.
Excel has a feature for doing this, the /Data /Table command. But it's not well documented. Each time I was asked to do something
complex using a Data Table, it took me a while to remember how to do it. So I developed this recipe. It may seem like a lot of
steps, but it's actually very straightforward and can be done in minutes.
Step 1.
Make a copy of your original workbook, and use that to work with in the following steps. (Always make a backup before attempting
anything big or new.)
Step 2.
Just an informational step. So that you can keep things clear, we will be dealing with three pages, called:
Source WS (worksheet): The big table of input data you want to work with, such as the 500 employees' data. Aside from making
it row oriented in the next step, this will not be edited/affected in any way.
Model WS: Your existing worksheet which calculates one set of inputs at a time. This will only have its input cells changed,
in Step 6.
Data Table WS: A new worksheet with the Data Table, including its results. This is where almost all your editing will be done.
Step 3.
Import your source data into an Excel worksheet (of course). This is the "Source WS". All the data (input variables) for each
Source WS record must be on one row (line). So work your data into a one-row format, if it covers multiple rows per input
situation. If you have extra columns of data, they don't matter; just leave them. All that's needed is that each row of input data
has all its data on one row. Input columns do not have to be next to each other.
Step 4.
Now on to the good stuff.
In your Source WS, define Names (Insert /Name /Define) for the columns you need as input. If the columns have a header, do not
include the header in the name. So the first line of the named area should be the first line of your variable data.
Step 5.
Insert a new sheet into your workbook. This is your "Data Table WS".
Across row 1, starting in column B, fill the column headers (text) with the input column headers as defined in step 4.
In A2, enter the number 1.
In B2, enter the formula =INDEX(SourceColumn,A2), where SourceColumn is just an example of a Named range you created in step 4. Do
this for all the input variables.
Step 6.
On your Model WS, make all your Model's input cells refer to the input columns of row 2 of the Data Table WS. So the first Model
input field now has "=DataTable!B2" as a formula, instead of an input value, the second one "=DataTable!C2", etc. Do this for all
the input fields in the Model.
Step 7.
Extend your Data Table WS to receive output by making new column headers in Row 1, to the right of the input columns. (Actually,
they don't have to be to the right, as long as you keep things straight.)
Now make the output fields in row 2 of the Data Table WS refer to the output fields of the Model WS. Just simple references like
"=Model!C37" or "=Sheet17!C37".
Step 8.
Test it. Enter a number in A2 and check that it retrieves the correct input from the Source WS and generates the correct output,
all on this one line.
Step 9.
Starting in A2, fill down a series of consecutive numbers (1,2,3...), for however many Source records you have. Don't use a
formula for this; use the fill handle, the Edit>Fill>Series command, fill it in by hand, use a +1 formula and convert using
Copy/Paste Special/Values - anything that will make it a "hard" number, NOT a formula.
Step 10.
On the Data Table WS, select A2 to the last line and the last column of the table and then /Data /Table. In the dialog box, leave
"Row input cell" blank. In the "Column input cell" box, enter A2.
Click OK, and see your table filled with input data and computed results. Voila! How long did it all take... 7 minutes?
Step 11 (optional).
The results that have been output to the Data Table rely on a formula, as you can see if you move the cursor to their cells. They
should not be "trusted" to not change. So, if you want to paste the results back into new output columns in the Source WS, you can
use: /Copy /Edit /paste Special /Values. But if you want your new Source WS output columns to dynamically reflect the Data Table
output columns, you can use e.g. "=DataTable!G32".
Note that if you use Paste Special: Values, they will lose any formatting you might have had on the Data Table WS, but are now
hard numbers in the Source WS. By the same token, Paste Special: Values will not change formatting in the Source WS, so your
Source columns will keep the same format if you gave those columns a format, and then Paste Special: Values into the Source WS
from the Data Table WS from time to time.
| Hello,
|
| I am trying to conduct a "what-if" analysis for a fairly simple financial
| model. This model is basically one extensive income statement that contains
| historical data as well as forward-looking statements. Historical data is
| hard-coded while the forecast data is driven by revenue, expense, and other
| miscellaneous assumptions. At any given point, I want to manipulate the
| revenue assumption for the upcoming period to see what the effect would be,
| not only on that period, but for all future periods.
| Clearly, the easiest way to do this would be to punch in different
| assumptions to see what the outcome would be. However, I want to develop
| something that would outline multiple outcomes (for example, 10%, 30%, or 50%
| growths) of these revenue adjustments all at the same time.
| I tried using scenarios (under Tools>Scenarios) and that works great except
| that it cannot show multiple outcomes all on one page at the same time. I
| messed around with "Summary" function under scenarios, but those outputs seem
| gear towards one-time analysis rather than for something that would need to
| be revisited each month. I was wondering if there is any other way to get the
| Scenarios to "publish" the effects of different inputs as a separate report
| that has more functionality and transparency.
| I also tried using data tables, which work fine if I just want to see
| different outcomes for one period, but if I want to see how those one period
| changes would affect other future periods, I would need to build additional
| steps to implement it into my main model (toggle switches, etc.)
|
| Any help/insight will be appreciated!
|
