Effect of interventions on % appointments not attended Effect of interventions on % appointments not attended. DNA, did not attend. UCL, upper control limit. Effect of interventions on % appointments not attended. DNA, did not attend. UCL, upper control limit. LCL, lower control limit. Elizabeth Tan et al. BMJ Open Qual 2017;6:e000093 © Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/