by Don Johnston | Nov 25, 2021 | Optimisation, Replenishment
Using a target service level to set safety stocks prevents optimisation. That is because the optimum service level is different for different items. Using the same target service level for all items tends to produce results which are far from optimal. This problem is...
by Don Johnston | Nov 9, 2021 | Inventory Strategist, Replenishment, Uncategorized
You can find out how good your reordering criteria (minimum and maximum levels) are by comparing their effects with those of near optimal criteria. There is open source software which can be used for this purpose. Instructions for downloading, installing and using it...
by Don Johnston | Sep 12, 2021 | Announcements, Inventory Strategist
This is my first post for some time. That is because I have been concentrating of developing open source software to facilitate improvement of inventory management. Facilities currently available include ABC analysis, service level measurement, ascertaining the scope...
by Don Johnston | Nov 26, 2018 | Announcements, SIMS
Open source service level measurement software is now available. For details, click on the “SIMS” tab. For information about the technique which the software uses to measure overall service level, see my article on that subject.
by Don Johnston | Nov 25, 2018 | Announcements, Inventory Management Basics
I will consider two definitions of service level. One is the probability that the next customer demand will be supplied immediately off the shelf. This definition is often used in theoretical work. It is applicable to both individual items (products) and the entire...
by Don Johnston | Nov 3, 2018 | Announcements, Inventory Management Basics, SIMS
Open source ABC analysis software is now available. For details, click on the “SIMS” tab. For information about ABC analysis, see my article on that subject.
by Don Johnston | Jan 3, 2018 | Uncategorized
The technique described here is called “exponential smoothing”. It is a simple method of updating an average as new data becomes available. It is the basis of most techniques used for forecasting customer demands. It was discussed briefly in the article entitled...
by Don Johnston | Jan 3, 2018 | Announcements, Forecasting
Some incorrect formulae were found in the simulation spreadsheet described in the article entitled “An Educational Inventory Management Simulator”. They have been fixed.
by Don Johnston | Mar 5, 2017 | Forecasting, Replenishment
This article contains information concerning the mathematics involved in the spreadsheets which are described in Part 1. That article was revised on 5 March 2017 and the spreadsheets were revised on 19 February 2017. It is assumed that the readers of this article have...
by Don Johnston | Feb 1, 2017 | Forecasting, Replenishment
Replenishment decisions rely on forecasts of lead times amongst other things. If the mean lead time for an item is not expected to change much then the average of recent lead times for the item can be used. Unless that item is purchased frequently, there won’t...
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