Difference between revisions of "Category:Dimension"

Revision as of 08:41, 9 September 2008

This page describes common and important dimensions in open assessments. For a description about the essence of dimensions and their operationalisations (indices), see Index.

Scope

Dimension is such a property that can have specific values or locations and that can be used to discretise or conditionalise variables or assessments along these locations. This page describes such dimensions that effectively categorise the content of any environmental health impact assessment.

To increase the usability of objects in open assessment, it is advisable to use uniform structures whenever possible. Also dimensions (and indices) should be uniform from one assessment to another as much as is practically possible. This page offers generally applicable dimensions.

What are dimensions that are

• important for fulfilling assessments,
• needed often in different kinds of assessments,
• general in nature so that they are applicable to a large number of assessment?

Definition

Each dimension should be useful for describing some important aspect of an assessment (or a part of an assessment).

Interpretation of a value

• An exact value for a particular location
• An integrated value (average or sum) for a range of locations

Locations for time

• Like other dimensions
• Current (the point in time that is described by the variable changes but is always unambiguously defined to the current time point)

Types of indices

• an arbitrary index
• a standardised index
• a continuous index

There are two kinds of dimensions.

• the variable has several values at the same time along the dimension (like a concentration field)
• the variable is about a random individual in a group (like body weight). The variable has a value for each individual, which can be classified along a dimension e.g. age. Not all age locations have observations, and there is not a requirement of continuity from one age point to another. However, if the variable is about the average body weight, it is continuous and has a value at evergy age point because then it is a prediction of the weight of a person of that age.

Developmental stages of variables

Result

These dimensions should be included for environmental health impact assessments:

• Activity sector
  • From economic classification of e.g. gross domestic product
• Emission source
  • How does this differ from economic classification? Probably more concrete.
• Pollutant
  • From Goodman and Gilman
• Environmental compartment
  • Air, water, soil, flora, fauna
• Exposure route
  • Food, drinking water, ingestion (non-food), breathing, dermal contact, sensory
• Health impact. It has at least two subdimensions:
  • ICD-10: An international classification of diseases. This is a discrete dimension, and the individual locations are hierarchically structured. In principle, the classification is exhaustive and covers all possible diseases at some level of precision.
  • Severity: mortality, morbidity.
• Non-health impact
  • Probably very diverse
• Decision
  • Very diverse, only criteria is that there is a decision-maker that can make the decision.
• Calendar time
  • Real time described as a year, date, and time. Based on Gregorian calendar. Theoretically, this is just one example of Reference time dimension, where the reference point is fixed to a standard event (Jan 1, 1 AD).
• Category:Reference time: time since (or before) a particular event in real time. The reference point must be defined in the context where reference time is used. Note that if the reference points of two reference times are unknown, the two reference times are sub-dimensions of the main dimension Reference time. They form a two-dimensional space within the main dimension. When the reference points become known, the other subdimension is known with zero degrees of freedom given the other subdimension; thus, the two subdimensions simply merge into one dimension.
  • Age: Age is a particular reference time dimension, where the reference event is the birth of the individual under examination.
• Geographical location. There are several possible ways to use subdimensions:
  • Spatial dimension based on a standard reference point, e.g. longitude/latitude. Theoretically, this is just one example of Location from reference point, where the reference point is standardised (0°E, 0°N). This has three subdimensions:
    • Longitude: The distance in degrees from the Prime meridian.
    • Latitude: The distance in degrees from the equator.
    • Height.
  • Country: A discrete dimension for geographical location. Country is based on the administrative boundaries of independent countries. For a complete list, see List of countries.
• Location from reference point
  • Spatial dimension based on a reference point defined in the assessment, e.g. location of the emission.
• Person or group
  • Any list of individuals or groups. Used for e.g. describing variability or roles of different groups.
• Sex
  • A discrete dimension describing the biological sex of an individual. Possible values: male, female.
• Species
  • Any animal or plant species. Used for food species as well as ecological assessments.
• Valuation
  • Any kind of list for different valuations. Especially useful for multiattribute utilities.
• Cost type
  • A list for different valuations that can be expressed in monetary terms.
• Step
• Sample: A discrete dimension for a random sample of values drawn from a probability distribution. It is a sequence of integers 1, 2, 3,...n, where n is the sample size. Within one model, all variable results for each location in sample must be coherent. In the result database, this dimension is described within the Result table, not in Location table as all others.