Level of Information Need (LOIN)

What Level of Information Need means in ISO 19650 — the purpose-driven framework that defines exactly how much geometry, data, and documentation a model element needs, and no more.

Level of Information Need (LOIN) is a framework for defining how much information a model element should carry — geometry, data, and documentation — at a given point in a project. It is defined in ISO 19650-1 and detailed in the European standard EN 17412-1:2020. Its core idea is deceptively simple: deliver exactly the information needed for a specific purpose at a specific milestone, and no more.

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The point of LOIN

It exists to prevent both under-delivery (not enough information to make a decision) and over-delivery (modelling detail nobody asked for, which wastes time and clutters the model). The right amount of information is whatever the next decision requires.

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A note on the name

The official ISO/EN term is "Level of Information Need" (singular). You'll often see it written "Level of Information Needed" — same concept, same acronym (LOIN).

Information need is driven by purpose

LOD-style ladders ask "how developed is this element?" LOIN turns the question around and asks "what do we actually need to know about this element, and what for?" Every information requirement is anchored to four things:

Purpose — why the information is needed (e.g. to estimate cost, to coordinate trades, to operate the building)
Milestone — when it must be delivered (the information delivery point)
Actor — who delivers it and who receives it
Object — what it applies to (an element, a system, or a whole asset)

Because the requirement is pinned to a purpose, two identical-looking walls can legitimately need very different information. A wall in an early cost model needs little more than its area and a generic type; the same wall in a facilities handover needs the actual product, fire rating, and maintenance documents.

The three components of LOIN

EN 17412-1 breaks the information need into three independent parts. Crucially, they are specified separately — you can ask for a lot of one and little of another.

Geometrical information — the shape and its handling: detail, dimensionality, location, appearance, and parametric behaviour. (Older frameworks called this the Level of Geometry, or LOG.)
Alphanumerical information — the non-geometric data: identification and properties such as material, fire rating, U-value, manufacturer. (Older frameworks called this Level of Information, or LOI.)
Documentation — associated files that aren't part of the object data itself: manuals, certificates, warranties, drawings.

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Geometry and data are decoupled

This is the big shift from LOD. A heating valve might need almost no geometry (a simple symbol is fine) but rich data (model number, flow rate, service life). A structural connection might need detailed geometry for clash checking but very little attached data. LOIN lets you say exactly that.

"Just enough" in practice

Specifying LOIN well means resisting the urge to model everything to the same level. For each object and each milestone you decide: what geometry resolves the question at hand, what data feeds the decision, and what documents need to travel with it. Anything beyond that is effort spent on information no one will use.

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Example

For a planning submission, an external wall might need: geometry accurate enough to read elevations and areas (geometrical), a generic construction type and overall U-value (alphanumerical), and no attached documents. For the same wall at handover: as-built geometry, the specific manufactured system, fire and acoustic ratings, and the product datasheet and warranty (documentation).

Where LOIN fits

LOIN is part of the ISO 19650 way of working, the international standard for managing information across a project. It superseded the earlier UK PAS 1192 approach (which paired Level of Detail with Level of Information). If your project is run to ISO 19650 — common across the UK, Europe, and increasingly worldwide — the exchange information requirements will be expressed as levels of information need, not as a single LOD number.

The US-originated Level of Development (LOD) framework answers a related but narrower question on a fixed 100–500 scale. The two are often confused; see LOD vs LOIN for how they compare and when each applies. New to the bigger picture? Start with What is BIM?