Developing a Health Unit

Although ENL has not yet reached the stage where a health unit can be precisely defined for the purpose of empirical measurements, the first step in this direction has been taken: a physical health index (PHI).

The PHI, described more fully below, is intended to help analysts assign scores to the health states of individuals, and thus to quantify value and cost. Although immature, it can be used in its present state to develop a provisional health unit.

The PHI measures the level of an individual's health. What ENL requires to measure value and cost, however, is the lived experience of health. This means that we must consider the level of health over a period of time.

For example, if a foundry worker loses the use of a leg due to an industrial accident, his or her PHI will decrease by a certain amount. But the worker could lose this functionality for a few days, a few months, or permanently. The time element is thus fundamental for estimating the cost the worker incurs.

The same is true for consumption—an increase in PHI from consuming a certain quantity of vegetables could last for minutes, hours, or days. The time dimension is therefore crucial for estimating value as well.

This implies that the health unit must be defined in terms of both the change in PHI and the period of time over which this change persists. These two dimensions are depicted in the following figure.

 Health unit ENL’s measurement unit has two dimensions: a change in the level of physical health and the duration of this change.

In this simplified example the individual's initial health level increases due to the consumption of an output with positive value. This causes health to rise for a period of time before dropping to its original level. The value gained from this consumption is the shaded area at left.

At a later time, the individual incurs a positive cost in production, causing a drop in their health level. The damage suffered is not permanent, so the health level rises to its original level at a later time. The cost that was incurred is the shaded area at right.

Reality is obviously much more complex than this, and the changes will be gradual rather than abrupt. Nevertheless, the principle is clear.

In ENL graphs the vertical axis is usually designated as "marginal health". Note that this refers not to the PHI itself, but to areas such as those shown in the above figure, which express the combination of health level and time. When the term "health unit" is used, this refers to an arbitrary division of such areas.

# Physical Health Unit

Reasonably accurate quantification of an individual's health level can be achieved in ENL through the application of the physical health index (PHI). Such indexes are common in the field of health measurement and have been constructed for a variety of purposes.1

One PHI, for example, permits the evaluation of social policies relating to assisted living facilities. Another helps to assess the need for medical interventions. ENL's PHI is intended to reflect the health changes resulting from consumption and production. It is based on the high-level abstraction shown in the following figure.

 General PHI model The physical effects of economic activities on the human body can be measured through changes in the body's capacity to interact with the outside world.

ENL is primarily concerned with the physical effects of economic activities on the human body. These effects can be measured through changes in the body's capacity to interact with the outside world.

Such interactions include the use of speech, the five senses, the sexual organs, and the four limbs, plus the vitality, strength, endurance, resilience, etc. required to make these interactions efficient and enjoyable.

Following the prevailing convention within the health measurement field, these people-world interactions are referred to as functioning. This term should not be confused with "functional theories" relating to economic theory.

For the purposes of this model, the human body is seen as a combination of vital and non-vital structures.

Non-vital structures are ￼￼those that do not cause death when they are destroyed. This holds true for the senses, the limbs, and the other components associated with functioning.

Vital structures are those that do cause death when they are destroyed and their activities are not replaced. This holds true for many internal organs, such the heart, liver, lungs, intestines, kidneys, and brain.

The non-vital structures interact with the world, thus accounting for much of humankind's experiences, while the vital structures provide physiological support for the non-vital structures.

The following figure shows the PHI model in more detail.

 Detailed PHI model ENL's physical health index combines measurements of the health of the vital and non-vital structures of the human body.

Most health indexes range from zero (death) to either 1.0 or 100 (maximum achievable health). The PHI model used in ENL adopts 0 for death, but a socially-determined number for maximum health. This is discussed below.

Some current health indexes permit negative numbers on the assumption that certain excruciating health experiences can be deemed "worse than death". This possibility must be recognized in the medical field to judge the need for medical intervention, but it has little relevance to economics and is not used in ENL.

Based on the abstraction above, ENL's PHI is a combination of the health of the vital structures and the health of the non-vital structures. This means that two sub-indexes are required.

These are called the support index for vital structures and the functioning index for non-vital structures.

The overall index must be constructed in such a way that the complete loss of any vital structure results in a PHI of 0 — that is, death. There is no such requirement for the complete loss of a non-vital structure.

Consider the support index first. The effectiveness of the heart or liver in performing its intended tasks can be scored on a scale of 0 (non-operation) to 1.0 (full operation). Because the vital structures are internal and can only be analyzed by specialists, this score must be assigned by a medical expert, based on empirical tests.

The functioning index differs significantly from the support index. Unlike the vital structures, the non-vital structures are external and mediate the human experience of the world. They can thus be assessed by the non-specialist, and establishing their maximum scores is a matter of non-specialist judgment.

The absolute scores assigned to fully effective non-vital structures are irrelevant. What matters is their relative scores, reflecting the relative importance of these structures to the social group.

For example, an eye could be given an arbitrary maximum score of 100, and the group could be asked which fully operational limb or limbs (if any) they would sacrifice to keep the eye. The details of such surveying and data interpretation must be left to experts in the field. The result of their efforts will be a set of relative scores for the non-vital structures that can be summed to give the maximum score for the functioning index.

The actual effectiveness of an eye, arm, etc. in performing its evolved tasks can, like a vital structure, be scored on a scale of 0 (non-operation) to 1.0 (full operation). This score can be assigned by a medical expert, based on empirical tests, in conjunction with the person's experience in using the structure.

The health measurement field is highly mature in making such joint determinations.

To meet the requirement that a score of 0 for any vital structure results in a PHI of 0, the individual vital scores can be multiplied together, and the support index can be multiplied by the functioning index.

Alternative mathematical operations are possible, and should be considered by experts.

Summarizing the above mathematically, using V1 etc. for vital structures and NV1 etc. for non-vital structures, we have the following:

Support Index (SI) = V1 * V2 * … * Vn

Functioning Index (FI) = NV1 + NV2 + … + NVn

Physical Health Index (PHI) = SI * FI

Following are several examples for illustration. For simplicity, assume that there are only three vital structures and three non-vital structures. Each non-vital structure has an assumed maximum score of 100, for a maximum functioning index of 300.

#### Example 1

A non-vital structure is lost. The other non-vital structures, and all vital structures, have perfect scores.

FI = 100 + 100 + 0 = 200

SI = 1.0 * 1.0 * 1.0 = 1.0

PHI = 200 * 1.0 = 200

#### Example 2:

Two non-vital structures lose 60% of their operational effectiveness. The other non-vital structure, and all vital structures, have perfect scores.

FI = 40 + 40 + 100 = 180

SI = 1.0 * 1.0 * 1.0 = 1.0

PHI = 180 * 1.0 = 180

#### Example 3:

A vital structure loses 50% of its operational effectiveness. The other two vital structures, and all non-vital structures, have perfect scores.

FI = 100 + 100 + 100 = 300

SI = 1.0 * 1.0 * 0.5 = 0.5

PHI = 300 * 0.5 = 150

(The partial failure of a single vital structure means significant health loss.)

#### Example 4:

All three vital structures lose 60% of their operational effectiveness. All non-vital structures have perfect scores.

FI = 100 + 100 + 100 = 300

SI = 0.4 * 0.4 * 0.4 = 0.064

PHI = 300 * 0.64 = 19.2

(The partial failure of multiple vital structures means massive health loss.)

#### Example 5:

A vital structure is lost. The other two vital structures, and all non- vital structures, have perfect scores.

FI = 100 + 100 + 100 = 300

SI = 1.0 * 1.0 * 0.0 = 0.0

PHI = 300 * 0.0 = 0.0