What is OAK?

OAK is the Operis Analysis Kit. It is a tool which adds to Microsoft Excel commands that are useful in developing and checking large spreadsheet models. It works with all versions of Excel from 2007 to 2016.

What’s new in OAK 4.4

The main innovation in OAK 4.4 is the splitting of the product between:

OAK Professional, with the same capabilities as before
OAK Essentials, which makes the four most popular OAK features at a more affordable price.

The two products are the same program. The set of features activated by the software is dictated by the licensing file present on the workstation. Upgrading from OAK Essentials to OAK Professional is just a matter of updating the license: no new software needs loading.

Some significant technical changes have been made internally to the product. These, and a log of changes from release to release of version 4 can be found in the reference material.

In particular:

The Map workbooks command can now color range consistency with different colors for each direction.
The Summarize workbooks command includes a cross reference report to show the number of linkages between worksheets.

On a more technical note:

OAK now uses the .NET Framework 4.5.2
OAK no longer requires Microsoft Office Primary Interop Assemblies installed.
OAK no longer has separate installers for 32-bit and 64-bit Excel.

OAK 4.4 capabilities

Full compatibility with Excel 2007-2016, including ribbon interface and large spreadsheets (which, of course, make the performance all the more valuable).

OAK Essentials

OAK can provide in seconds a quick overview of an unfamiliar spreadsheets

a list of all the worksheets in a workbook, plus key statistics such as number of formulas

a sortable list of every formula that is distinct, ie not just a copy of its neighbour, along with a measure of its complexity so that the longer, more error-prone examples can be identified and prioritised

a list of the constants, which can then be checked against source documentation

a sortable list of every formula, along with a count of the number of occurrences of a selection of formula elements, which are weighted to produce an overall risk score

a diagram showing a bird’s eye view of the patterns in each worksheet, showing where formulas are copied consistently and inconsistently and where named ranges lie.

OAK pioneered the capacity to compare spreadsheets in a way that is actually usable, distinguishing changes that are real from ones that are merely the consequence of items changing position.

provides systematic version control to developers and users of spreadsheet models

gives financial model auditors the means to accommodate late changes to financial models in the minutes before a transaction closes

relevant to spreadsheet inventories of the kind made necessary by Sarbanes Oxley and other regulatory regimes.

OAK Professional

Click on areas of the OAK ribbon to see the OAK help relating to each command.

In addition to the above capabilities, OAK Professional can help you develop your own spreadsheets

get suggestions for optimizing formulas, so that they perform the calculation you are attempting more neatly

OAK offers ground-breaking facilities for deciphering the workings of individual spreadsheet calculations

reconstruct a formula, to receive automated re-performance of specified calculations, and understand which cells they act on

prune a formula, to make a calculation easier to understand by showing only the elements that are actually active at the current moment

identify the discrepancies that are preventing your attempt at a parallel reconstruction of a spreadsheet calculation from reproducing the original accurately, using the Fan out Precedents tool.

OAK offers rich options for managing Excel names

produce a sortable list of all the names in a workbook and their locations and characteristics

change your mind about the choice of names, even after they’ve been extensively referred to in your spreadsheet. (Excel 2007 has at last added something similar, ten years after OAK provided the facility; users of earlier versions of Excel can benefit from this.)

remove names from your formulas, and turn them back to conventional coordinate notation: if you like to develop spreadsheets using names, but your customer doesn’t understand them or doesn’t like them, you can strip the names out before shipping the worksheet; conversely, if you receive a spreadsheet that makes extensive use of names in formulas, but you are more comfortable with the coordinate notation, OAK will make the necessary transformation for you.

OAK can also

insert rows and columns even when they intersect merged cells, arrays and data tables (which defeat the corresponding commands built into Excel)


To learn more about OAK, you can study the documentation online, or download a browsable help file (Windows CHM format) or a printable copy (Adobe PDF) of the manual. The content is pretty much identical in all three formats.

Online helpDownloadable helpPrintable manual