Measurement of morbidity / a report of the Statistics Sub-Committee of the Registrar General's Advisory Committee on Medical Nomenclature and Statistics.

Date:
1954
Catalogue details

Licence: Public Domain Mark

Credit: Measurement of morbidity / a report of the Statistics Sub-Committee of the Registrar General's Advisory Committee on Medical Nomenclature and Statistics. Source: Wellcome Collection.

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    (b) Persons who experience more than one “ spell ” during the period of observation must be counted once only. (c) The relevant persons in the numerator comprise those with:— (i) Spells beginning and ending in the period, (ii) Spells beginning in the period and still continuing at the end of the period, (iii) Spells beginning before and ending in the period, (iv) Spells beginning before the period and still continuing at the end of the period. (d) if some persons are sick from more than one disease (i.e. at the same time or on successive occasions within the period of observation) and if, in using the rate in relation to individual diseases, such persons are counted for each of the diseases separately, then the rates for individual diseases cannot be aggregated to give the equivalent rate for all diseases combined. 4 (B). Proportion of persons sick at a point of time “ The number of persons who are sick at a given time divided by the number of persons exposed to risk at that time.” Short title:—“ Point Prevalence rate.” notes : (a) The rate will be numerically the same as rate 3 (B) above. (b) The number of persons may be based on an actual count at a specific point of time or may be an average calculated for a specific point of time. (c) If some persons are sick from more than one disease at the given time and if, in using the rate in relation to individual diseases, such persons are counted for each of the diseases separately, then the rates for individual diseases cannot be aggregated to give the equivalent rate for all diseases combined. V. *Measures relating to Duration 5. The average Duration of sickness per completed spell “ The total of the entire durations of all spells of sickness ending during a defined period divided by the number of spells ending during that period.” Short title:—“ Average duration per spell.” notes : (a) The relevant spells in the numerator comprise the whole of those spells of sickness which end in the period of observation and may thus include days of sickness prior to the period. (b) If rates are used in relation to individual diseases, the duration of a spell of sickness which relates to more than one disease should, in calculating rates for each of the diseases separately, either be assigned wholly to one of the diseases or be apportioned between the diseases concerned on some basis relevant to the object of the enquiry. (c) The average duration per spell may be misleading and the full frequency distribution, showing the numbers of spells of different durations, will often be required. 6. The average Duration of sickness per sick person “ The total of the entire durations of all spells of sickness ending during a defined * In other parts of the Report, the measures defined in this section have, for convenience, been referred to as rates.