When measuring W/A over time, a deviation from tracking (i.e. running parallel to) the median growth curve is indicative of either stunting or wasting (note the "-ing" ... denoting a process). Typically a slow deviation is stunting and a sharp deviation is wasting but using these case-definitions is tricky (simpler to distinguish "slow" ad "fast" if "thrive line" growth charts are used as they are in the UK). A more objective approach is to assess MUAC at the time of any deviation. If MUAC is low (e.g. < 125 mm or < 135 mm) then you have wasting. If MUAC is high then you have stunting. A child can be stunted (not the "ed" ... denoting an outcome) but still track the median growth curve. This is very common after the age of about 24-30 months. Stunting occurs earlier resulting in stuntedness which will probably persist until the pre-adolescent growth spurt at between 9 and 12 years. After 24-30 months a deviation is likely to be due to wasting but you should check this using MUAC. As an aside ... We have been seeing some good results using MUAC in GMP for CMAM case-finding (c. 90% coverage achieved) but have had great problems using W/H. It appears using W/A and W/H togther confuses and we end up with stunted and wasted children (i.e. both kinds separately and together) being referred and this results in the notorious coverage killer of rejected referrals. I hope this helps.