Example: Division into lots

[jpmckinney]

The discussion copied below from #888 relates to a specific jurisdiction, but these sorts of questions are common to other jurisdictions, and can form the basis of a worked example.

For #891, we will also need clearer guidance and consistent answers to these types of modelling questions.

@jpmckinney:

Can you explain what is meant by 'tender by items'? If the procedure is to award different items to different suppliers, then I believe, conceptually, that the items are in different lots. It might be the case that in the concrete system you are working on, a shortcut is taken to avoid the overhead of tracking/storing lots if each item is known to be awarded separately, but even in that case I think there are 'conceptual' or 'virtual' lots.

@yolile:

So, in Paraguay, we have three different awards methods:

• By Lots: each supplier can win one or more lots. If you win a lot you have to supply all of the items of that lot, example
• By total: you can only win all of the items, and the items are grouped in one big lot, example
• by items: each item can be awarded to different suppliers, there is not lots in the tender, example

@jpmckinney:

First, I want to be clear in distinguishing what I mean by 'conceptual' and 'concrete'. 'Concrete' means what you can directly observe from a real system in the real world. 'Conceptual' means an abstraction or inference or implication from the concrete, which is necessary for there to be any standardization across concrete systems. OCDS operates at the conceptual level, and all implementations of OCDS need to make some leaps from the concrete to the conceptual; otherwise, they are not using OCDS as a standard, but instead as a set of common 'building blocks' that have different semantics in different jurisdictions.

At a conceptual level, 'Lot' is the concept for organizing items that are to be supplied together. If there are no lots, the interpretation is the same as if there were one big lot, i.e. all items are to be supplied together.

Now, I understand that the implementation of public contracting into a concrete system in Paraguay has produced a method whereby there are no concrete lots. However, the items are nonetheless organized such that each item is to be supplied separately. This would mean that there are 'conceptual' lots, but, in this case, they have no representation in the concrete system.

If we were to model items as you suggest, then OCDS data users will need to apply special logic to correctly interpret Paraguay's data. They will need to know that if some flag is set indicating that the method is 'by items', then they must treat each item as if it is in a separate lot. If Ukraine were to pursue yet another model, then OCDS data users will need to apply more special logic, and so on. This leads to a situation where the data can hardly be described as 'standardized', and OCDS becomes a bag of words that countries re-use, rather than a standard with consistent semantics.

@jpmckinney:

Here's another way of thinking about it. Let's pretend that instead of 'Lot', the definition is called 'ItemContainer', and it is described as "A group of one or more items, where each group is bid on, awarded, and supplied separately. If a contracting process has no groups, it is interpreted as having a single group for all items." I think we would agree that, in Paraguay, in the 'by items' case, that it needs 'item containers' to model its procedure correctly – otherwise, 'by items' isn't distinguished from the 'by total' case.

In OCDS, 'Lot' is the word used for that concept. 'Lot' is not defined as "lot according to Paraguay law + lot according to Ukraine law + lot according to UK law," etc., because that would be an incoherent concept, because not all countries use the same words to mean the same things, and many countries use concepts implicitly in cases where it isn't relevant to be explicit. In OCDS, we unfortunately need to be very explicit to achieve standardization.

@yolile:

Ok so,
Paraguay -> OCDS
by item -> an item container (lot) per item - here the information about the simultaneousSupply goes to the lot
by lot -> an item container (lot) per lot - here the information about the simultaneousSupply goes to the lot
by total -> no item container at all - here the information about the simultaneousSupply goes to the item?

@jpmckinney:

For by total, I recommend having one (big) lot in lots.

(In #891 I propose that all OCDS contracting processes should specify an explicit lot, as otherwise there are two ways of modelling the same thing (either use tender as an implicit lot, or use lots with a single lot), which means that data users need to look in two places, and also need to reconcile potentially conflicting information between the tender and lots. In retrospect, it might have been a good idea to use a generic term instead of 'lot'.)

I'm not sure if people will agree with #891 (i.e. forcing the use of lots by all publishers), but for this case, it is not incorrect to use lots even if there is only one lot.