The gold standard for diagnosing VUR is still the voiding cycstogram (VCUG). These authors looked at the inter observer variability of grading of vesicoureteral reflux (VUR) using a VCUG and highlight the implications for treatment and prognosis as a results. They used the RIVUR trial (a randomised controlled trial looking at the treatment of VUR, grades 1-4, in children with prophylactic antibiotics after a urinary tract infection) to compare reporting by a clinical radiologist and two urologists used in the trial. The grading used was the International Reflux Study (IRS) scale of 1-5. Six hundred and two non-referenced reports from 90 centres were reviewed. Agreement by all three radiologists on VUR grade occurred in only 59% of ureters; 39% of ureter reflux agreement was obtained in two out of three radiologists. All three disagreed on reflux grade in 2% of ureters. Agreement was most at 95% in the low grade reflux one group. The other VCUG assessments (bladder shape, bladder neck, diverticulum, trabeculations, urethral features) had at least 92% agreement. The authors highlight some limitations of their study, such as non-attendance at the screening by the reference radiologists (a VCUG is a dynamic study), non-standardised technical equipment, and an inability to perform multi variable analysis on the interpreters of the study. The authors conclude that this considerable inter observer variation has both clinical and research implications as much treatment is based on VUR grading and study designs rely on its use.