Health and Functioning Assessment With Numeric and Symbolic Values

Introduction

In this chapter we point out the importance not to mistreat symbolic values in assessments as numeric values. It is common in Likert like scales to understand the ordinal scale as a sequence of numbers, so that a 5-scale is represented by the numbers {0,1,2,3,4} or {1,2,3,4,5}, and computing with the values in the scale becomes computing with numbers. Doing so ignores the logical nature of such a scale, where the extreme values represent good/bad or true/falls, and values in between represent levels of uncertainty with respect to the extreme values.

A typical finite and ordinal scale is provided within ICF (International Classification of Functioning, Disability and Health), as part of WHO-FIC (World Health Organization - Family of International Classification) classifications), which involves computing with its generic 5-scale of values. We will show how a logical-algebraic approach to computing with these values is done utilizing algebraic structures represented by quantales. We will also show how the 6^th and 7^th values annotated with ICF’s core 5-scale can be integrated into the computations. Those additional 6^th and 7^th values enable us to compute with missing and incomplete data. Conventional data analysis using numerical and statistical methods is unable to handle missing data in these ways.

The WHO Family of International Classifications and Terminologies includes the International Statistical Classification of Diseases and Related Health Problems (ICD), the International Classification of Functioning, Disability and Health (ICF), and the International Classification of Health Interventions (ICHI). These are the so called Reference Classifications that “serve as the global standards for health data, clinical documentation and statistical aggregation”.

Apart from the Reference Classifications, there are other classifications including International Classification of Diseases for Oncology, International Classification of Primary Care, International Classification of External Causes of Injury (ICECI), Technical aids for persons with disabilities, The Anatomical Therapeutic Chemical Classification System with Defined Daily Doses (ATC/DDD),International Classification for Nursing Practice (ICNP), Verbal autopsy standards: ascertaining and attributing causes of death tool, and The Startup Mortality List (ICD-10-SMoL).

For ICF (ICF, 2001) there is the main English version and additionally there are translations to a number of languages, and more translations are desired. ICF was officially endorsed by all 191 WHO Member States in the Fifty-fourth World Health Assembly on 22 May 2001 as the international standard to describe and measure health and disability.

Items in the four components of ICF are arranged in a hierarchical structure, where items appear under sections, sections under chapters, and chapters within components.

• Component

• Chapters

• Sections

• Items

Some items further subdivide into subitems. There are four components, the first of which is 'Body functions'. Here is an example of items in a section in a chapter:

• Body functions

• Body structures

• Activities and participation

• Environmental factors

• Chapter 3 Support and relationships

• Global mental functions (b110-b139)

• b110 Consciousness functions

• b114 Orientation functions

• b117 Intellectual functions

Each item can be qualified, and qualifiers appear in a 5-scale:

• xxx.0 NO problem

• xxx.1 MILD problem

• xxx.2 MODERATE problem

• xxx.3 SEVERE problem

• xxx.4 COMPLETE problem

• xxx.8 not specified

• xxx.9 not applicable