1. Descriptors of service granularity
Sharing Common Functionalities
Joni Karanka, ONS

2. Context
All initiatives that deal with sharing services across institutions have to deal with service granularity
However, we do not currently have good descriptors of granularity to support sharing

3. Uses of granularity descriptors
Across NSIs, descriptions of statistical service granularity can be used for:
Describe services in the service catalogue for adopting organisations to assess the service
Support the scoping of service development
Support the development of policies around service identification, development and sharing

4. The granularity model 2 dimensions: granularity and cohesion
Granularity uses GSBPM to describe the functional level the statistical service supports
Cohesion describes how closely the service aligns with the GSBPM functional level it supports

5. Granularity Cohesion Description in GSBPM Level of phase (level 1)
Very coarse
Service contains a full GSBPM phase (e.g., dissemination)
Service contains related activities of more than one phase (e.g., design and dissemination of metadata)
Service contains functionality from several phases (e.g., design, collection, management and processing of data)
Level of sub-process (level 2)
Coarse
Service contains a full GSBPM sub-process (e.g., editing and imputation of statistical data)
Service contains related activities of more than one phase (e.g., editing and imputation, and related design activities)
Service contains unrelated functionality from several sub-processes (e.g., classification, editing, imputation, aggregation and production of outputs)
Level of business function (level 3)
Fine
Service delivers a clearly defined business function below the level of sub-process (e.g., design collection instrument)
Service delivers several related business functions from different phases (e.g., design collection instrument, provide collection instrument)
Service contains unrelated business functions from several phases (e.g., design collection instrument, provide collection instrument, load data, code data)
Level of services or utility services that support a business function
Very fine
Service delivers a micro or utility service that can support a business function
Service delivers several related micro or utility services
Service delivers several unrelated micro or utility services
Cohesion
Fully cohesive
Complementary
Heterogeneus
Fully covers one function at specified granularity
Most functionality relates to one function at specified granularity, complemented with functionality from another phase or sub-process
Contains functionality from several phases or sub-processes

6. Fully cohesive, very coarse
Level 1
Phase
Level 2
Sub-process
Level 3
Business function

7. Heterogeneous, very coarse
Level 1
Phase
Level 2
Sub-process
Level 3
Business function

8. Complementary, coarse Level 1 Phase Level 2 Sub-process Level 3
Business function

9. Fully cohesive, fine grained
Level 1
Phase
Level 2
Sub-process
Level 3
Business function

10. Examples of use
Provide clear description of development intention: “we are creating fully cohesive fine grained services, we will provide an interface”
Agree policy: “services in the catalogue have to be at least coarse grained and not heterogeneous”