Through researching the topic over the last decade, IDTechEx have encountered thousands of different companies (e.g. maintaining a database of over 1200 companies), had site visits, face-to-face meetings and telephone interviews with several hundred of these companies, and have included key data from many of these conversations throughout the report.
The approach of looking by sector, but then observing the bigger picture of how these sit under the "wearables" banner reveals some very interesting trends from recent years. For example, IDTechEx track a series of relevant metrics to understand the "state of the industry", including search trends, patent trends, investment data (funding and number of rounds), number of product launches, and key revenue and product shipment volume data across each of the 48 product forecast lines included in the report. When aggregating trend indicators together, it is possible to see the clear hype curve for wearables, peaking in 2015 and falling since. This hype curve actually correlates relatively well with the growth rate in the overall industry, increasing to a peak at 36% growth between 2014 and 2015, but falling to the 10-20% range per year ever since. However, despite the clearly reduced hype, this growth has led to a doubling in annual revenue generated in the sector in this time. This data is summarized in the following figure.
IDTechEx - www.IDTechEx.com