Open Property Data Association
Smart Property Data Trust Framework
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    Connect meanings across contexts

    An exchange succeeds when the recipient understands the relevant meaning. Give definitions an accountable home and inspect exactly what a proposed correspondence preserves, loses or invents.

    Editorial watercolour of two practitioners comparing one sheet outside separate established reading rooms while keeping their own reference folios distinct.

    The same word can be doing different work

    “Completion” could label a transaction event or the finishing of a document-preparation task. “Property” could point to a dwelling, a building or a record of rights. A shared label is not enough to make those meanings interchangeable. The practical question is what a recipient will conclude after information crosses the boundary.

    A bounded context is an explicit boundary within which meanings and their ownership are maintained consistently. Its semantic home identifies responsibility for a definition. This is not permission to invent conflicting facts: it is a way to preserve legitimate differences in the questions a model answers.

    Work within the documented boundaries

    The boundaries for this development phase are established inputs, not something each reader or workshop must rediscover. OPDA's maintained contextual-boundary register names these 6 property semantic homes:

    The Common boundary has a different job: stable exchange meaning genuinely shared by several contexts. It stays deliberately small and is governed through the Interoperability Working Group. A term does not belong there merely because several applications use it, or because nobody has yet resolved its ownership.

    The DBT Smart Data scheme working group addresses scheme-level questions. Separately, the candidate register includes a machine-proposed DBT Smart Data semantic context for authorisation and controlled sharing. That candidate context is not the external government programme, not an OPDA working-group decision and not a seventh property-domain bounded context.

    Four useful ideas, not four interchangeable boxes A profession supplies expertise, a working group organises participation, a system handles records and a semantic context owns a meaning within its stated boundary. Profession Expertise and practice Working group People organised to contribute System Where records are handled Semantic context The stated home of a meaning
    1. A profession is a field of expertise and practice; members may contribute to several groups.
    2. A working group organises people. Its membership does not by itself define a semantic context.
    3. A system handles records. One system can handle meanings from several contexts.
    4. Established semantic contexts locate meaning and responsibility. No one-to-one mapping between these four ideas is asserted.

    A surveyor is a person with professional knowledge. A working group brings people together to review meanings. A software system may display survey reports, transaction records and listing information. A semantic home identifies responsibility for a particular meaning. The same professional can contribute evidence to several questions, and the same system can use meanings from several homes.

    For example, someone working on a property-data platform may identify an ambiguity in a lending participation record. Their employer's product does not automatically move that meaning into Property Technology. Follow the documented ownership and ask the responsible people to review the distinction. Within a context, resolve contradictory definitions; do not use a mapping to disguise a disagreement in its own language.

    Compare full definitions before drawing a bridge

    The following is a fictional vocabulary comparison, not a mapping in the candidate. Both lists concern physical access during one identified visit to the same nonempty set of identified agreed areas, and use the same meaning of “accessed”. Their scopes differ in one important respect.

    Source vocabulary · teaching version 1

    Some access: at least one, but not all, of the identified agreed areas was accessed.

    Includes access to two of three areas. Excludes access to none and access to all.

    Recipient vocabulary · teaching version 1

    Restricted access: not all of the identified agreed areas were accessed.

    Includes access to two of three areas and access to none. Excludes access to all.

    A useful correspondence can still lose meaning For the same identified set of areas, some access means some-but-not-all; restricted access means not-all, including none. The first is narrower, not an exact match. Recipient: restricted access Not all of the identified areas — includes none Source: some access Some but not all of the same identified areas None accessed Also fits recipient Source → recipient can lose detail. Recipient → source can invent access. Fictional proposal for review, not an accepted candidate mapping.
    1. Assume both fictional choices concern the same identified, nonempty set of areas.
    2. Source some access means some but not all. Recipient restricted access means not all and includes no access.
    3. The source meaning is narrower than the recipient meaning, not exactly equivalent.
    4. Forward conversion loses the distinction from none; reversing it could invent access. This is a teaching proposal, not a current accepted mapping.

    Every “some access” case meets the recipient's “restricted access” definition under these premises. The reverse does not hold: a “restricted” record could mean zero areas were accessed. Treating the concepts as exact substitutes would lose that distinction in one direction and invent some access in the other.

    An exact correspondence requires the relevant meanings to support that strong substitution. A close correspondence says the concepts are related enough for a stated use while remaining different; it is not simply an exact match with a lower confidence score. Broader and narrower correspondence express direction of scope. No correspondence may be justified when subjects differ or the evidence is insufficient.

    Record the definitions and versions compared, the intended use, counterexamples and the reason for the chosen relationship. An agreement about version 1 does not automatically cover a later definition that adds or removes cases. A useful mapping is a reviewable claim with consequences, not a line drawn because two labels look friendly.

    Keep the date the recipient actually needs

    Harbour Court's source account identifies an inspection on 12 August 2026, report version 1 issued on 14 August and version 2 on 20 August. Suppose a fictional recipient's definition of “inspection occurrence date” is “the calendar date on which the identified inspection took place”. A proposal fills it with the latest report issue date.

    The proposal supplies 20 August where the source and recipient meanings require 12 August. It does not preserve the requested meaning, even if both values are dates and the recipient successfully reads the record. The agreed exchange must retain the inspection reference, the occurrence date and the report version supporting the account. It must not redefine a report correction as another visit.

    Practice: when “completion” does not correspond

    In fictional glossary A version 1, “completion” means the transaction-transfer event identified as C in transaction T. In fictional task list B version 1, “completion” means the event of finishing preparation of document bundle D. The teaching record explicitly states that preparation finished on 7 September and C occurred on 10 September. These definitions do not claim to set professional or legal terminology.

    Worked response

    The supplied definitions identify different events, so an exact correspondence is not supported. Retain the task and transaction-event identities, their dates and any supported relationship between them. The shared word does not turn 7 September into the transaction's completion date.

    If glossary A were missing its definition, the correct review would first request it. That would be an evidence gap, not proof that the meanings must differ. In both cases the useful contribution names the subject, compared versions and consequence of substitution.

    Cooperation does not prove term equivalence

    A strategic context map can describe who supplies shared meaning and how contexts cooperate. An individual term mapping makes a separate claim about defined concepts. A relationship between groups does not establish that every similarly named term is equivalent, and its arrow direction is not automatically the direction of a term correspondence.

    In candidate 0.1.0-draft, the Common supply arrows show shared elements supplied from the Common boundary. They are not mappings. The maintained register currently contains 0 cross-domain mappings; its status is “awaiting working-group evidence”. The fictional bridges in this lesson must not be read as adopted additions to that register.

    Sometimes the best result is deliberate reuse. Sometimes it is a qualified connection that preserves a difference, or a decision not to map until evidence exists. The Interoperability Working Group's boundary work does not replace the domain owners' responsibility for internal meaning.

    Use Review choices and mappings to apply the comparison. The context-map and mapping-record references contain the separate formal contracts. Current boundary facts above come from the maintained candidate register, not from professional illustration or campaign copy.

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