Important outcome data from the PACE trial (White et al. Reference White, Goldsmith, Johnson, Potts, Walwyn, DeCesare, Baber, Burgess, Clark, Cox, Bavinton, Angus, Murphy, Murphy, O'Dowd, Wilks, McCrone, Chalder and Sharpe2011) appears to be missing from the paper describing recovery in ME/CFS (White et al. Reference White, Goldsmith, Johnson, Chalder and Sharpe2013) and the participants do not appear to have been asked whether they had recovered as a result of receiving cognitive behaviour therapy (CBT), graded exercise therapy (GET) or Pacing.

The paper would have been improved had three specific markers of recovery been reported. First is the receipt of a state sickness or disability benefit. Claiming such a benefit indicates that the person is still ill and has not recovered. This data was included in the cost analysis study (McCrone et al. Reference McCrone, Sharpe, Chalder, Knapp, Johnson, Goldsmith and White2012) that reported: ‘Receipt of benefits due to illness or disability increased slightly from baseline to follow-up.’

Second is employment or education status. The recovery paper argues that ‘Return to work is not, however, an appropriate measure of recovery if the participant was not working before their illness and is influenced by other factors such as the job market.’ However, a sustained return to meaningful paid employment, or education, or the ability to do so, is an objective marker of recovery.

Third is ability to mobilize. Recovery in a condition whose cardinal clinical features relate to mobility – exercise-induced muscle fatigue and weakness – must be matched with an ability to mobilize in a normal and timely manner. The overall results for all the treatments in the PACE trial relating to changes in the six-minute walking test from baseline to 52 weeks do not represent a return to normal levels of activity. It can be seen that the figures for all the treatment groups at 52 weeks are below the 402 m reported to be present in patients with class 3 heart failure (Lipkin et al. Reference Lipkin, Scriven, Crake and Poole-Wilson1986). So the results for those who had recovered – who should now be achieving a much higher distance – ought to have been included. In addition, the question could be raised as to how it is possible to meet the entry criteria for the PACE trial with a Short Form-36 physical function subscale score of 65 yet leave the trial as recovered with a lower score of 60.

The term ‘recovery’ implies a sustained return to symptom-free health with the ability to repeatedly and reliably participate in all aspects of normal life – employment, education, social activities, etc. Without this information it is difficult to conclude that these patients have in fact recovered.