Six weeks will always be the delivery time given for your new sofa regardless of where it is made, according to findings by a team of British mathematicians.

As part of research into logistics, academics at the University of Derby asked more than 70 furniture firms how long it would take to deliver a suite — and every one gave the 42-day period.

Transportation, waiting for the right colour and a need to follow what competitors do were all reasons for the stock industry-wide answer, said Stuart Berry, a senior lecturer in mathematics.

"Furniture makers would each quote the same delivery time but this quote was made without taking any notice of workload," he said. "They all said it would be ready in six weeks. It was a standard answer."

"No one wants to promise delivery inside six weeks as they cannot deliver but to quote any longer would risk losing custom to a rival."

In the same study, about 100 glaziers — or window fitters — quoted an average of four weeks for an installation date.

Berry and fellow academic Val Lowndes, who carried out the research as part of a post-doctoral study into logistics, believe the findings can be explained by a branch of maths called "fuzzy logic".

"There is an element of fuzzy logic in the initial findings," said Berry. "In mathematics terms, a form of knowledge which cannot be defined precisely can be classed under such logic."

The core concepts of fuzzy logic, said the academic, date back to the work of Polish mathematician Jan Lukasiewicz in the 1920s.

It enables computerised devices to reason more like humans and can help explain why such trends in industry exist, he said.

Berry’s team found that the average suite-making process involved one worker cutting the material, three others sewing and four more to assemble cushions.

In the average window-fitting process, one worker cuts the material, three workers assemble the frame and two finish the product.

The findings are to be followed up with further research which will involve a series of questionnaires being sent to firms to understand the time scale further.

More here.