Comparing a Walloon and a Flemish bill

Four structural differences precede any question of figures. They concern the framework, the breakdown, the units and the text.

Point	Under the CCTB	Under the Flemish framework
Nature of the document	citation	full transcription
Location of the technical text	in the framework	in the particular specification
Applicable version	the one cited in the contract	the one transcribed at drafting
Priority check	which version	is the text current

The consequence is that a Flemish item is often accompanied by its full text, whereas a Walloon item refers to an index. Comparing a Walloon heading with a Flemish text without reading the corresponding article of the framework leads to misjudging the content.

1. Identify both frameworks and their versions. That comes first. Under the CCTB the version is dated. Under the Flemish framework it is not always stated and must sometimes be inferred from the content.

2. Build comparison groups, not item correspondences. Group by elemental work, for instance all roofing works, rather than seeking a counterpart for each line. The divisions do not coincide.

3. Check inclusions in the text, not in the heading. A masonry item may include or exclude lintels, sills and protection. Those inclusions appear in the description of the article, and they differ between frameworks.

4. Check units and measurement rules. Two bills may express the same work in different units, or apply different deduction rules for openings. This point is covered in the article on item, quantity and unit.

5. Isolate what remains incomparable. Some items have no equivalent. Treating them separately is better than forcing a correspondence that would distort the whole.

Three areas resist, and it is better to know beforehand. They concern composite items, lump sums and measurement conventions.

Preliminaries and site set-up items. Their division follows largely from the practice of each framework and each author. Line-by-line reconciliation is illusory there.

Lump-sum works. A lump sum covers a scope defined by the text accompanying it. Two lump sums with the same heading may cover very different scopes, and the gap does not show in the bill.

Provisional items and global prices. Their conventional treatment differs, and an item without an amount does not mean the same as an absent item.

A useful warning, because the temptation is strong. No automatic correspondence between indexes exists.

The number of items is not an indicator. A bill with twice as many lines is not more precise; it is structured differently.

The rate per item is not transferable. Where scopes differ, the unit price of a Walloon item and that of a Flemish item with the same heading do not measure the same thing.

Only the total per elemental work compares usefully, provided both groups genuinely cover the same physical scope.

A practice that pays, particularly where the work must be justified or resumed later. It consists in documenting the reconciliation choices.

Keep a correspondence table stating, for each group, the items retained on both sides, the inclusions checked, the unit differences corrected and the items left outside the comparison. That table can be reread months later without reconstruction.

That table is also a protection. In a dispute it shows what was compared and on what basis, which a bare figure never does.

Three rules.

Allow the time. Serious reconciliation between two frameworks is not a matter of minutes, and underestimating it leads to rushing the inclusions stage.

Never conclude on a gap before checking scopes. Most apparent gaps come from there.

Flag incomparable areas explicitly in the output, rather than burying them in a total.