and disability assessment contracts. It said the cost of each WCA had risen from £115 under Atos to £190 under Maximus. The report went on to say that Maximus was facing "significant challenges with staff failing to complete training requirements" and revealed that in July 2015 - less than six months into the new contract - the DWP had been obliged to draw up a 'performance improvement plan' with Maximus because "volume targets were not being met". The NAO also declared that the DWP had "allowed bidders to make assumptions about staff training that it knew were overly optimistic and difficult to achieve" and implied that the target set by the DWP of one million assessments a year was too ambitious, saying: "One experienced bidder withdrew from the process because it could not meet the required number of assessments". The next month, the most senior official in the DWP told a parliamentary committee that of all the bidders for the WCA contract, only Maximus and one other unnamed firm had submitted bids that anticipated hitting the DWP's ambitious new target. Criticism of assessment credibility Apart from questions arising from the substantial proportion of 'fit for work' recommendations that have been disregarded by decision-makers or overturned by tribunals or by the DWP itself, concerns about the reliability of the WCA as an indicator of fitness for work have arisen from a number of other sources. The Work Programme firms responsible for training people in the Work-Related Activity Group said they had "ongoing concerns about the accuracy of the WCA" and rated earlier improvements to the WCA as only "4 or 5 out of 10". Outcome targets Professor Malcolm Harrington, the first external reviewer of the operation of the WCA, was asked by a parliamentary committee whether he had ever found any evidence that Atos assessors had been put under pressure to reach targets. He replied: In 2012, a GP posed as a trainee Atos assessor and recorded undercover video footage that was later broadcast by Channel 4's investigative current affairs programme Dispatches. In the film, trainers warned the NHS doctor that if on average he were to recommend more than one disabled person per day for the Support Group, he would be subject to an increased level of management scrutiny through a mechanism known as "targeted audit". The undercover doctor was told: An assessor on "targeted audit" would also no longer