Those files provide what, in absence of other methods, is perhaps the most reasonable way to derive such estimates.  Brief notes in the "Preface" tab of each file describe how to do so.

The estimates automatically revise when the user changes the amount of relevant parameters - which include:
(i) the percentage of the given country's annual imports from each of more than 50 countries of each major product form since the year 2000 which is "illegal";
(ii) the change in those percentages each year; and
(iii) the factors used when estimating roundwood equivalent volume.

The percentages of illegality mentioned in (i) and (ii) of the previous paragraph which the files present by default are a first iteration.  They will be modified on receipt of credible further information.  Currently they are consistent with percentages adopted in estimates made for Chatham House's assessments,[-] [-] extended to include the most recent time period.

One should only focus on refining the percentages for the bilateral flows of product forms which contribute most to the total.

The percentages reflect the strategic salience of particular illegalities, under three broad headings - governance, sustainability and development.  Illegalities which either are associated with the allocation of concessions (including to front-companies of otherwise ineligible entities) and the designation of land-use, or concern customary and other rights of forest peoples are of course fundamental to the legal production of wood-based products (and governance).  Those illegalities should be considered when assessing the legality of commodities produced on land which was recently cleared of natural forest (or produced on peat recently drained). 

Despite their fundamental salience, there does not appear to have been any effort by Competent Authorities, contractors, or civil society in the EU to address such legalities, especially in relation to direct or indirect imports from partner countries having VPAs whose scope does not include such illegalities.  The window of opportunity to highlight this through the EUTR is rapidly closing - the EU and Indonesia are in the final stage of developing their VPA prior to FLEGT-licensing.  However, not only is there doubt that countries (including the EU) can use trade to launder their obligations under international conventions by the outsourcing of infractions, but the FLEGT Regulation requires FLEGT-licensing to guarantee that the licensed products are legal.

The legacy of past illegality is particularly relevant (if it has not been foregiven), especially concerning enterprises which are also exploiting what used (until recently) to be naturally forested land in order to produce other commodities.

Illegalities under the heading sustainability would include having and implementing credible plans to sustainably manage concessions.  If no such legal requirement exists (or the requirement is not consistent with sustainbility) then the question "Why?" should be considered. 

Illegalities under the heading development would reflect the extent to which forest- and export-related taxes, fees, penalties, etc are both properly paid (and subsequently allocated to local communities as required) and, ideally, set at levels which are equitable and optimise government revenue.  Other such illegalities would also consider compliance with quotas for milling prior to export.

When adopting a percentage of illegality for a given product under a particular heading, it is necessary to estimate the proportion which derives from forest clearance, from plantations, and from natural forest.  The latter should be segmented in order to reflect the extent to which the supply is credibly certified as legal and - perhaps more salient - from sustainbly managed forest.

The largest percentage of salient illegality for a given partner country, product form and year should be adopted in the files to which links are provided above.

There appears to be little evidence that systematic attempts have been made to identify salient illegalities in countries with which the EU has or is negotiating VPAs.  There is similarly little evidence that attempts have been or are being made to identify how best (and in what sequence) to address those illegalities, recognising their interdependence.  In addition to being fundamental to optimising the FLEGT Action Plan and management of VPAs, such considerations would be useful (especially if communicated strategically) when  seeking to re-establish progress where VPAs have stalled.

The VPA Legality Assurance Systems which have been devised are implicitly inflexible (at least one official audit suggests, might not even be feasible), and to that extent tend to constrain progress.