Counts of Dengue reported in MALAYSIA: 1963-2011

Project Tycho datasets contain case counts for reported disease conditions for countries around the world. The Project Tycho data curation team extracts these case counts from various reputable sources, typically from national or international health authorities, such as the US Centers for Disease Control or the World Health Organization. These original data sources include both open- and restricted-access sources. For restricted-access sources, the Project Tycho team has obtained permission for redistribution from data contributors. All datasets contain case count data that are identical to counts published in the original source and no counts have been modified in any way by the Project Tycho team. The Project Tycho team has pre-processed datasets by adding new variables, such as standard disease and location identifiers, that improve data interpretability. We also formatted the data into a standard data format.

Each Project Tycho dataset contains case counts for a specific condition (e.g. measles) and for a specific country (e.g. The United States). Case counts are reported per time interval. In addition to case counts, datasets include information about these counts (attributes), such as the location, age group, subpopulation, diagnostic certainty, place of acquisition, and the source from which we extracted case counts. One dataset can include many series of case count time intervals, such as "US measles cases as reported by CDC", or "US measles cases reported by WHO", or "US measles cases that originated abroad", etc.

Depending on the intended use of a dataset, we recommend a few data processing steps before analysis:
- Analyze missing data: Project Tycho datasets do not include time intervals for which no case count was reported (for many datasets, time series of case counts are incomplete, due to incompleteness of source documents) and users will need to add time intervals for which no count value is available. Project Tycho datasets do include time intervals for which a case count value of zero was reported.
- Separate cumulative from non-cumulative time interval series. Case count time series in Project Tycho datasets can be "cumulative" or "fixed-intervals". Cumulative case count time series consist of overlapping case count intervals starting on the same date, but ending on different dates. For example, each interval in a cumulative count time series can start on January 1st, but end on January 7th, 14th, 21st, etc. It is common practice among public health agencies to report cases for cumulative time intervals. Case count series with fixed time intervals consist of mutually exclusive time intervals that all start and end on different dates and all have identical length (day, week, month, year). Given the different nature of these two types of case count data, we indicated this with an attribute for each count value, named "PartOfCumulativeCountSeries".

Project Tycho数据集收录全球各国上报的法定报告疾病病例数统计数据。Project Tycho数据编审团队从各类权威数据源提取上述病例数，此类数据源通常为国家或国际卫生主管机构，例如美国疾病控制与预防中心（US Centers for Disease Control）与世界卫生组织（World Health Organization）。上述原始数据源涵盖开放获取与受限访问两类资源。针对受限访问资源，Project Tycho团队已获得数据提供方的再分发许可。所有数据集收录的病例数统计均与原始发布数据完全一致，Project Tycho团队未对任何统计数值进行修改。Project Tycho团队已完成数据集预处理工作，新增标准化疾病与位置标识符等变量以提升数据可解释性，并将数据统一整理为标准格式。

每份Project Tycho数据集仅针对特定疾病（如麻疹）与特定国家（如美利坚合众国）收录病例数统计，病例数按时间周期上报。除病例数统计外，数据集还包含相关统计的属性信息，如统计地点、年龄组、亚人群、诊断确定性、感染来源以及数据提取来源等。单个数据集可包含多组病例数时间序列，例如"美国疾病控制与预防中心上报的美国麻疹病例数"、"世界卫生组织上报的美国麻疹病例数"以及"境外输入性美国麻疹病例数"等。

根据数据集的使用场景，我们建议在开展分析前完成以下数据处理步骤：
- 缺失值分析：Project Tycho数据集未收录未上报病例数的时间周期（由于源文档不完整，多数数据集的病例数时间序列存在缺失），用户需自行补充无统计数值的时间周期。需注意，数据集已收录病例数为0的时间周期。
- 区分累计与非累计时间序列：Project Tycho数据集内的病例数时间序列可分为"累计型"与"固定周期型"两类。累计型病例数时间序列由重叠的统计周期组成，所有周期起始日期相同，但结束日期各异。例如，某累计型统计序列的每个周期均始于1月1日，结束日期分别为1月7日、14日、21日等。公共卫生机构通常会以累计时间周期的形式上报病例数。固定周期型病例数序列由互斥的时间周期组成，所有周期的起始与结束日期均不相同，但周期长度一致（如日、周、月、年）。鉴于两类病例数数据的性质差异，我们为每个统计值新增了名为"PartOfCumulativeCountSeries"的属性，以区分其类型。