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Resupply management

Table of contents

Resupply management

The second tab in the IRT setup is dedicated to parameters entered in the IRT systems, often specific for each country, and that define how sites and depots will be resupplied.
This is where you will be able to play with the IRT parameters, even when the trial is live, to optimize the resupply strategy.

In the Resupply management for sites and Resupply management for depots tables, you can specify which values to use for:

  • Short window: it is the minimum number of days that the inventory on site should be able to cover, at all times. As a good practice, it is recommended to use a value that is a bit higher than the lead time (a couple of additional days, for example).

  • Prediction window: the length of the prediction window will determine how often sites and depots are resupplied. For example, if the prediction window is 28 days at sites, the shipments will contain enough kits to cover the sites needs for 28 days (on average). The longer the prediction window, the bigger the quantities sent when a shipment is triggered, meaning that less frequent shipments will be needed but the overage might increase.

  • Minimum storage period (MSP): this parameter is a constraint on kits being allowed to be shipped or not when they approach expiry. It determines a number of days during which any kit that arrives on site or depot should still be valid. For example, a MSP of 15 days at site will ensure that any kit arriving at site can still be dispensed to patients during at least 15 days.
    Having a long MSP ensure that kits are not sent to sites when they have a good chance of expiring after a few days, triggering a new shipment right after getting on site. However, it will imply that some kits about to expire are blocked at depot level earlier than with a shorter MSP, increasing waste a bit.

These three parameters have to be defined for every country, depot and package type. If the same values apply to multiple countries or package types, you can benefit from the multi-selection feature to enter those data in a single line.

💡 Tip 

When launching the simulations, the user can specify a multiplier (PWM or Prediction Window Multiplier) to be applied on the prediction windows of the sites and/or the depots. This can help investigate multiple prediction windows without the need to duplicate the IRT setup.

Buffer levels

In the Buffer levels table, you enter the buffer levels to use in the trial, if they are fixed already or if you want to test some values.

For all countries and package types that do not have buffers levels defined, the algorithm will compute the buffers during the simulations and provide them in the simulation results.

❗This is applicable only when buffer levels are not defined for the whole duration of the trial. If you enter buffer levels only for a specific period of time, the system will not compute any buffer levels for the rest of the duration.

✅ The good practice is therefore to either (for a specific depot/site groups and package type) :

  • Define buffers levels for the whole duration of the trial.

  • Not define any buffers so the system will compute them.

The two values to enter are:

  • The trigger level (or min buffer level) that will be used to trigger shipments whenever the stock on site reaches levels that are too low. The trigger level is computed to cover the unexpected dispensing that can happen during the short window (to cover a bit more than a lead time). It is based on observations in the simulations, taking into account the “worst case”. What is called “worst case” can be chosen with the SSCL parameter.

  • The resupply level (or max buffer level) that will be used to compute the quantity to send to sites when a shipment is raised. The resupply level is computed to cover the average amount of unexpected dispensing that can happen during the prediction window. Having a high resupply level can help reduce the number of shipments, but will increase the waste.

These values are defined per country, package type and for a certain period of time. The date to enter in the table is the start of the period on which the buffers apply, and they will be applied until the next defined period or until the end of the trial.