this document was supplied by the depositor and has been modified by the HDS SN 7390 - Disease in the Royal Navy during the Nineteenth Century, 1856-1898 Royal Navy data in the 19th century: Factors affecting data quality. Copyright Vaughan Dutton, Wellcome Unit for the History of Medicine, Oxford Contact address: Wellcome Unit for the History of Medicine, 4547 Banbury Road, Oxford, OX2 6PE Between 1840 and 1899, the Admiralty produced annual Statistical Reports of the Health of the Royal Navy. Disease data was collected by medical officers on board Her Majesty’s naval ships and relayed back to London, where it was condensed into general reports annually. These reports provide a longitudinal overview of health throughout the Royal Navy, covering almost 70 years. They are therefore a valuable resource for 19th medical history. This paper evaluates the a range of factors that impacted on the quality of this important dataset Introduction The data provides a quantitative record of disease in the Royal Navy from 1856 to 1898. During this time, disease was recorded by medical officers on board naval ships, and reported to London on a regular basis. Naval clerks would then condense these records into annual Reports on the Health of the Royal Navy. The data presented in these databases are gathered from these reports. Database A: Diseases in the Royal Navy by geographical station Time period: 1871-1898 (27 years). Number of cases or respondents: The data are presented as summary statistics of entire naval stations, each of which included several thousand individuals (the average total size of the Royal Navy during the 19th century was 52000). There are 9 naval stations, which together reflect the entire British maritime empire. Number of variables: Data is reported for each of the 9 stations. For each, 19 different disease categories are reported. Each of these categories is reported for morbidity, invaliding and mortality. In total, therefore, there are 46 variables for each of the 36 years. Number and format of data files: This database consists of one data file in Excel format, containing 28 worksheets/28 files in Tab delimited text format. Database B: Total force mortality disease and non-disease This database presents mortality figures for the entire Royal Navy from 1856 to 1898. These are disaggregated by disease and non-disease causes. Number of cases or respondents: Each statistic represents, on average, 52000 individuals. Number of variables: 2 variables: disease mortality and non-disease mortality Number and format of data files: 1 data file in Excel/Tab delimited text format Introduction In 1836, the Lords Commissioners of the Admiralty ordered the compilation of Statistical Reports of the Health of the Royal Navy (SRHN). Disease data was to be collected by medical officers on board Her Majesty’s naval ships and relayed back to London, where it would be compiled into reports on an annual basis. Thus, the SRHNs provided an overview of the state of health throughout the Royal Navy. The first SRHN was published in 1840 and annual editions continued almost uninterrupted into the 20th century, except for a period between 1849 and 1856 as a result of resources being diverted to the Crimean war effort.1 The first three editions (1840, 1841 and 1852) differed from subsequent editions by providing a retrospective of naval disease for the decade before 1840. Thereafter, the SRHNs reported disease data for their year of publication only. Considered as a whole, then SRHNs include almost 70 years of 19th century naval disease data, making it a potentially valuable resource for historical epidemiologists interested in the period. Moreover, the quantitative data is supplemented by qualitative description and explanatory notes, thereby providing valuable insight into some of the key factors underlying disease rates. The ‘catchment area’ of the data was incredibly broad: during the period, the Royal Navy (RN) enjoyed a near global presence, with the British maritime empire subdivided into a number of geographically defined Stations. These included the Home, Mediterranean, North American and West Indies, South East Coast of America, Pacific, China, East Indies, Australia, and West Coast of Africa and Cape of Good Hope Stations. The underlying structure of the SRHN reflects this geographical arrangement, with each Station being treated in a separate chapter. Additional chapters present data related to health in the Irregular Force (ships which traveled between Stations), Royal Marines embarked, and various naval dockyards and hospitals. Finally, there was an overview section considering the navy as a total force. Chapters all followed the same format and throughout the period there was very little variation to the layout and disease nomenclature, making for easy chronological and spatial comparisons. The reports therefore amount to a geographically extensive and longitudinally coherent record of nineteenth century disease in the RN and as such have great potential to contribute to 19th century historical epidemiology. While range and volume of the data are impressive, its quality and reliability is not self­evident. Historical quantitative data is subject to a range of potential pitfalls, not all of which are obvious. This paper aims to evaluate the SRHN data in light of these pitfalls, thereby throwing some light on its quality. The paper will proceed with an overview of the SRHN data, after which they will be evaluated according to a range of threats to data quality. These include the introduction of bias as a result of the motivation behind its collection 2; missing data and incomplete records 3; problems with nomenclature 4; accuracy in original data observation (diagnosis) 5. Other 1 C. Lloyd and J Coulter, Medicine and the Navy 1200­1900, iv, (London, 1963), 273. 2 G. Alter and A Carmichael, ‘Studying Causes of Death in the Past: Problems and Models', Historical Methods, 29, (1996), 44­48. 3 C. Mathers, 'Counting the dead and what they died from: an assessment of the global status of cause of death data', Bulletin of the World Health Organisation, 83:3, (2005), 171­177. 4 G. Alter and A. Carmichael, 'Studying Causes of Death in the Past: Problems and Models', Historical Methods, 29 (1996), 44­48. 5 S. Preston, Mortality patterns in national populations, (New York, 1976), 76 N. Williams, 'The Reporting and Classification of Causes of Death in Mid­Nineteenth Century England', Historical F. Meslé, and J. Vallin, 'Reconstructing Long­Term Series of Causes of Death', Historical Methods, 29, (1996). 2 issues include subclinical diseases 6; and recurrent disease. Overview of the SRHN data The creation of the SRHNs occurred within broader events in England and Europe. While the production of ledgers of disease, including quantitative data relating to disease had long since been collected by institutions prior to the mid 19th century, it was only during the first decades of the 19th century that it became possible to imagine sickness as being subject to statistical laws of nature.7 Moreover, during this period it became increasingly possible to understand these laws of nature by investigating the accumulated numbers. As a result of this new found knowledge, a host of new bureaucracies emerged in order to collect information about populations and disease and deposit them into well organised data banks.8 This ‘era of enthusiasm’ ran from approximately 1830 to 1849, during which time public statistics attracted public interest to a high degree in many major European centres.9 In England, civil registration of vital statistics was established, under the Registrar General; similar steps were taken in Denmark, France, Germany, Prussia, Holland and Norway. Several statistical congresses were also arranged in the European centres and statistical associations sprang up. In the subfield of vital statistics, the Registrar­General of England made headway in using quantitative data to explain epidemic phenomena. Furthermore, it is during this period that disease nomenclature was improved and the notion of cause of death much refined.10 British administrative apparatuses were disinclined to integrate statistical knowledge and expertise into bureaus which depended on them. These existed, but they were far more scattered than in other European countries, such as France.11 Beyond the administrative sphere existed another sphere of scholars and researchers and these two spheres remained autonomous but informed each other. The production of the SRHN data tables was therefore on a par with wide ranging developments across Europe, i.e., a belief that quantification could reveal the iron laws which controlled disease and facilitate their mastery.12 Each chapter of the SRHN is divided into three subsections reflecting three levels of disease severity ­ cases, invalidings, and deaths. Between 1830 and 1878, individual diseases were reported at the level of the ship, making the ship the unit of analysis. After 1878, diseases were reported at the level of Station, with only some disease rates being reported at the ship level; the rationale for this abandonment of detail was the result of the Parliamentary Committee on Official Statistics' move toward standardising tabulations and data across the services and the obvious irrelevance of ships in this scenario.13 There is also, in each chapter, tabulations of absolute loss of service from disease and injury and average 6 J. Gay, 'Epidemiology Concepts for Disease in Animal Groups', retrieved 7 June 2013 <http://www.vetmed.wsu.edu/courses­jmgay/documents/GroupEpidemiologyConcepts.pdf>. 7 I. Hacking, 'Biopower and the Avalanche of Printed Numbers', Humanities in Society, 5, (1982), 279­95. 8 ibid., 286. 9 H. Westergaard, Contributions to the History of Statistics (New York, 1932). 10 ibid., 236. 11 A. Desrosieres, The Politics of Large Numbers (Cambridge, Mass., 1998) 12 E. Higgs, Making Sense of the Census: The Manuscript Returns for England and Wales, 1801­1901,(London, 1989) 13 BPP, Statistical Report on the Health of the Navy, for the year 1870, in Navy (health) (ed.), (1872) , 15.