IPSMS Qualifiers - Encoding Schemes

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Controlling Data ('Encoding Schemes')

Encoding schemes identify the rules or authoritative lists used to control the content of a given field. They facilitate metadata creators by

providing lists of terms from which they can choose the appropriate name or term, or
indicating the form of the name, term or entry to use.

They help eliminate inconsistency in data entry by reducing the likelihood of variant or incorrect forms of the same name or term being used, and ensure that within and across organisations personnel are using the same name forms and terms. Ensuring such consistency across records improves the chances of the appropriate resources being retrieved as the result of a search.

Value encoding schemes are supported directly in HTML <meta> elements, using the attributes scheme and language (lang).

An encoding scheme may indicate the standard determining the format by which

a date is entered (e.g. ISO 8601 stipulating date in format yyyy-mm-dd)
language is indicated (e.g. ISO 639-1 stipulating language entry, e.g. 'en')

Note:

The IPSMS approves the ISO 8601 standard for date form entries
(yyyy-mm-dd).

The lang attribute is used to specify the language of the content of the metadata element. It is not to be confused with the DC.Language element, which indicates the language of the content of the resource.

Use of the lang attribute is not essential to the metadata record.

Recommendation:

Recommended best practice is to use the two-letter language code taken from the ISO 639-1 standard. For example, 'en' for English, 'ga' for Irish.

Recommendation:

It is recommended that a controlled vocabulary be used in conjunction with the Subject element. The lead agency maintains such a controlled vocabulary, known as the Public Service Thesaurus ('PST').

Recommendation:

It is recommended that a controlled vocabulary be used in conjunction with the Type element. The lead agency maintains such a controlled list, known as the Irish Public Service Document Type list ('IPSDT').

Note:

In order to comply with the IPSMS, Version 1.0, documents matching any one of the six approved document types listed on the IPSDT list must so indicate the document type in the metadata DC.Type element

Currently, there are only six valid entries included in the IPSDT list of document types;

legislation

policy

report

form

press release

speech

The government search engine will scan sites for these document types and present them in date order on the Government Home Page. This will allow browsers to follow recent developments across all government departments at a single location or to be alerted of recently published, e.g., Acts or policy proposals.

Recommendation:

It is recommended that where terms are taken from a controlled list, the controlled vocabulary should be indicated using the 'scheme' indicator.

Examples:

Note:

Where a scheme or lang is specified, the value must be encoded according to that scheme.

Example:

<...scheme="IPSDT" content="legislation">

NOT

<...scheme="IPSDT" content="statutory instrument">

['statutory instrument' not being a term from the IPSDT list]

Note:

Agencies or organisations may input values from their own controlled vocabularies if they so desire. The IPSMS does not place restrictions or exclusions on the use of controlled vocabularies.

Where agencies or organisations are using controlled vocabularies not explicitly recommended in the IPSMS, they are asked to register the controlled vocabulary with the lead agency. This may help ensure that conflicts do not exist between vocabularies being used.

Examples of the use of encoding schemes

1) Indicating that the entry in the DC.Title field is in English:

2) Indicating that the document type entry ‘press release’ is taken from the IPSDT controlled list of terms:

3) Indicating that the date format used (yyyy-mm-dd) conforms to the ISO 8601 standard:

4) Indicating that the subject terms are taken from the Public Service Thesaurus (PST):