Getting Started with TIME
TIME is freely downloadable as part of Spectrum, which you can obtain from either here or from the Avenir Health website. If you aim to use TIME to explore policy questions, we strongly encourage you to contact the TIME team at LSHTM for advice and access.
Knowledge of TB epidemiology and TB care and control is important. The TIME team at LSHTM can provide technical assistance and answer specific questions you may have during the modelling process.
Who to contact
If you are considering using TIME to model the TB epidemic at the national or sub-national level, you should first assess the data availability in your specific setting. In particular, you should consider the data needs for calibration listed in the table below.
You will need to consider additional data to model interventions in TIME. If the intervention you’d like to model is pre-specified in TIME, data needs are clearly laid out in TIME; and while defaults are provided we recommend using local data to inform the model.
Table: Data needs for model calibration in TIME and suggested data sources
|Demographic data and projections||UN Population Division|
|GTB estimates for incidence, prevalence, mortality, notifications||GTB*|
|HIV burden and ART coverage||UNAIDS|
|Estimated number of individuals screened (preferably trends)||NTP**|
|Diagnostic algorithms and coverage||NTP|
|Linkage to care (trends, by MDR)||NTP, literature (MDR, GTB)|
|Treatment success, by MDR (trends)||GTB|
|Prevalence survey results||NTP|
|Drug resistance survey results||NTP|
|HIV prevalence + ART coverage (required if high HIV burden setting)||GTB, NTP|
|Proportion of TB in children (<15 years old)||NTP|
|Current coverage and efficacy of TB programme activities||NTP|
|Size of risk groups and TB prevalence||NTP|
The screening workbook [download] is a framework for calculating the sensitivity and specificity parameters for TIME Impact. The user is provided with estimates of sensitivity and specificity from the literature for recommended symptom-based screening tools, chest X-ray, smear microscopy, GeneXpert and clinical diagnosis.
Within this framework, the user, either external TA or in-country expert, needs to think about and have a strong understanding of the diagnostic pathways that are implemented in the country. For each diagnostic pathway, the user is able to calculate the net sensitivity and specificity using the estimates and equations provided. Then, the user can set the coverages of each pathway and the workbook will calculate the average net sensitivity and specificity based on the coverages and the net values for each pathway.
The workbook can be used for both HIV- and HIV+ individuals, since the sensitivity and specificity of tools may be different for these. The user can explore what the average net sensitivity and specificity will be under different case finding strategies (for example, scale up for GeneXpert) and input these into TIME Impact to estimate projected impact on the TB epidemic.
Data collation workbook:
The data collation workbook [download] is a space that provides the user with the opportunity of collating epidemiological and programmatic data in one place. The workbook is broken down into two parts: epidemiological targets and programme parameters.
For epidemiological targets, the user collates data for epidemiological indicators of notifications, mortality, prevalence and incidence, number of individuals presumed to have TB, MDR-TB and TB/HIV. The workbook asks for the value and range for each data, the year it refers to and the source. These are then referred to during the calibration process as targets to be matched in TIME Impact.
For programmatic parameters, the user collates operational data that refers to the cascade of care such as average net sensitivity and specificity (calculated by the screening workbook), proportion of individuals diagnosed with TB who start treatment and treatment success. Programmatic parameters are available by MDR and HIV status.
It is expected that TA and in-country partners work together to collate data and have discussions on the quality of the estimates available as well as discussions on the trends observed in the epidemiological indicators. The notifications trend should be broken down into different parts and in-country partners are expected to provide expert opinion (or scientific evidence) on why the trend looks the way it does, taking into account, for example potential under/over-reporting or any major changes in activities that may have led to the trend looking the way it does. If an Epidemiological Review is available for the country, then this is a good source to consult when trying to gain a deeper understanding of the data.
Through the data collation process, data gaps may become evident or some data that is available is not high quality. This should lead into discussions on how data can be strengthened or how new operational data can be collected through research.
*Global TB Programme
**National Tuberculosis Programme