To answer the first question the first question. The goal of NCLB was for all students to meet the criteria for 'proficiency' (which was defined by state testing and attendance data) by 2012. Starting in 2002, schools were evaluated on the basis of these tests, and a cut score was used to determine whether or not adequate yearly progress was made. If progress was not made, the schools were sanctioned. The more years the schools did not meet AYP, the sterner the sanctions. The percentage of student proficiency was raised a certain percentage every year, until 100% proficiency was the goal. As predicted, no schools had 100%  of students performing at grade level in 2012, so they rewrote the law, and now we have ESSA. 

Also, the measurement instrument changed several times over the years, bringing into doubt the reliability and validity of the evaluation. So, the 'goal posts' were moved in two ways.