from Colin Kennedy, managing director, Market21, Sydney, Australia

Sir; Your article ‘Gaps in the action’ (April 3) was intriguing. The problem of availability of product to the shopper is not confined to the UK, nor is the frustration felt by suppliers that retailers are not doing enough to address it. The issue occurs in many countries.
However suppliers are not always helpful.
Survey results taken to retailers showing out of stocks are 9%, or whatever level, are neither informative nor helpful. What does 9% mean? That, of all the times someone went into a store to look for a product it could not be found. So what do I do with that?
It does not differentiate between an out of stocks at peak sales time vs 7am on Tuesday. The effect on the shopper and subsequent lost sales is significantly different.
Neither does it tell me how
long the out of stock situation lasts, or when it started.
A simple percentage measure is both dangerous and naïve.
The starting point should be - what do we need to know to stop out of stocks occurring in the first place?
Market21 has developed the following approach: effectively measure out of stocks, detect the patterns, determine the probable causes of out of stocks and fix the problem.