According to the provided text, how is FTT identified in children?

Failure to thrive (FTT) in children is identified primarily by evaluating their growth patterns, specifically through percentage rankings on growth charts. These growth charts compare a child's weight, height, and head circumference to established percentiles that reflect growth within the population. When a child's measurements fall below the third percentile or show a significant drop in percentiles over time, this may indicate FTT. By focusing on these growth metrics, healthcare providers can identify concerns regarding a child's nutritional intake, medical conditions, or other factors that might impede healthy growth and development. This method offers a quantifiable and standardized approach to assessing a child's well-being in terms of growth, which is critical in determining appropriate interventions or further evaluations.