IR35 – Government’s CEST tool produces undetermined outcome

Published on: 17/12/2020


The Government’s CEST tool, designed to help determine whether a worker will be caught by the changes to the off payroll working rules (IR35) was unable to reach a conclusion in 19% of cases checked in the last year.

In data released by HMRC, between 25 November 2019 and 24 November 2020 the CEST tool delivered 975,416 outcomes. Of these outcomes:

  • 505,598 (52%) found the worker fell outside the IR35 rules;
  • 281,099 (29%) found the worker would be inside IR35; and
  • 188,719 (19%) were undetermined.

HMRC note in its comments alongside the data that in ’more finely balanced cases’, the tool will produce an ‘undetermined’ outcome and advises users to refer to their detailed IR35 guidance to make their decision on whether a worker falls within IR35.

Responsibility for making these status determinations is due to shift from the worker to the ‘end user’ client on 6 April 2021, but specialists such as Qdos have voiced concerns that the tool still is not ‘up to scratch’ following its update in November 2019 and will leave users without the clarity they need to make these decisions.

There are currently no plans to update the CEST tool further, as HMRC believe adding in the more complex questions needed to reach an outcome in more cases would make ‘increase the burden’ for most people using the tool. They will however publish this data on a quarterly basis going forward, in a bid to improve user confidence in the tool.

Should you have any queries about IR35, including about status determinations, our employment team is on hand to help.


This information is for guidance purposes only and should not be regarded as a substitute for taking professional and legal advice. Please refer to the full General Notices on our website.