The study was renewed in 2005 to define new national norms for pediatric blood pressure by adjusting the available data set of over 60,000 pediatric blood pressure readings for age, height and gender among children of normal body weight. The study will (a) broaden the percentiles presented so as to display the full range of blood pressure percentiles from the first to the 99th percentile (b) evaluate the percentiles for children of normal body weight so as to disentangle the relationship between hypertension and obesity (c) provide a algorithm using Microsoft Access for computation of a blood pressure percentile or Z-score in a user-friendly format (d) provide percentiles for both K4 and K5 diastolic blood pressure (the Task Force Report only includes percentiles for K5 DBF) and (e) compare childhood blood pressure percentiles by ethnic group. The study will also develop screening rules for detecting high blood pressure in children. Given the existence of new Task Force Norms that quantify percentile values of blood pressure in children by age, sex and height, an significant issue is how to use these norms to effectively screen children for high blood pressure, where high blood pressure is defined as having an average blood pressure > 95' percentile for a given age, sex and height based on task force percentiles over a large number of visits. The goal is to develop efficient screening rules that maximize accuracy with the fewest screening visits necessary per child. The screening rules will be assessed in simulation studies and tested in a sample of 16,000 Houston school children who were screened for high blood pressure