Using Derwent Classification to improve your subject searching

Search Tips - July 2000

In the last Search Tip we looked at Electrical Patents Index Manual Codes (EPI Manual Codes) and explained that these can be used to improve the result of a subject search in Electronics & Electrical Engineering and related topics. EPI Manual Codes (and Chemical Patents Index Manual Codes too, for chemical topics) are part of a hierarchy, the broadest level of which spans all areas of technology. This broad level of the hierarchy is known as the Derwent Classification.

One or more Derwent Classes are applied to all Derwent World Patents Index database records and they have a multitude of uses in searching (even though at first glance they might appear to be too broad and too general). You can, for instance, use them to cover a large subject area very quickly - for example the whole of footwear could be covered with Derwent Class "P22" without the need for thinking of all the words that could possibly describe footwear (e.g. shoes, boots, soles etc).

The use of Derwent Classes in combination with other online search terms, for example words, gives you a simple and effective way to restrict your search to a specific subject area. This is particularly useful when the words you are using in your search are ambiguous, as the following example will show.

Using Derwent Classification on Dialog: Search Example

Using Derwent Classification on Questel.Orbit: Search Example

Using Derwent Classification on STN: Search Example

Contact the Customer Services Help Desk for a free copy of the Derwent Classification Manual. Alternatively, you can call the Help Desk on +44 (0)20 7344 2999.

For further assistance please contact your local Derwent Help Desk.