IDC has said that the worldwide tablet market is expected to see a “massive deceleration” in growth for the full year 2014, slowing to a 7.2 per cent increase from 52.5 per cent in 2013.

For the full year, market shipments are expected to reach 235.7 million. And looking further out, the company expects even further slowing, forecasting 5.4 per cent CAGR in the period to 2018, by when the total will have reached 285.9 million units.

The company’s latest figures indicate how volatile the tablet market is. Earlier this year it cut its tablet growth forecast. But this was followed by a strong Q3, driven by a strong performance in the US – a market that has been seen as having reached maturity.

At the heart of the matter for 2014 is that Apple is set to see the first full year of declines in iPad shipments since launch, and this device is a key bellwether in the market. In addition, replacement lifecycles for tablets have continued to grow, to resemble PCs more than smartphones.

“We believe the two major drivers for longer than expected tablet lifecycles are legacy software support for older products, especially within iOS, and the increased use of smartphones for a variety of computing tasks,” said Ryan Reith, program director for IDC’s Worldwide Quarterly Mobile Device Trackers.

IDC also said that “significant advancements have been made recently by hardware manufacturers to advance the 2-in-1, or detachable product category”. But despite thinner devices, lower prices, and greater product choice, shipments are only expected to reach 8.7 million units for the full year, due to “hesitancy around the Windows 8 platform, which the majority of 2-in-1 devices are built on”.

And looking forward, there are a “few unknowns” which could impact tablet shipments, including the reaction to Windows 10, Google’s plans with its Android and Chrome platforms, and Apple’s rumoured iPad product line diversification.