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 2000 to 2016.

What’s new in OAK 4

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

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

Innovative and technically ambitious commands that seek to clarify the intent of complicated calculations, going much beyond simple precedent tracing.

Various enhancements to the already market-leading ability to compare spreadsheets.

Exposure of all the functionality to COM, so that it can be driven by VBA and similar programming environments, allowing favourite review processes to be automated.

More robust handling of spreadsheets written in languages other than English.

More capable setup utilities, capable of diagnosing and overcoming many obstructions to installation in the more locked down environments typical of global financial institutions.

Much more extensive help and documentation.

OAK 4 capabilities

OAK can help you develop your own spreadsheets

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

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

OAK offers rich options for managing Excel names

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 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 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

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

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

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

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.


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