As per the performance ratings presented in the graphic chart, 'Ed' is the teacher who displays the most variable or fluctuating during these five years. <u>His performance has remained shifting constantly from (1 to 4 between 2005-06, then from 4 to 2 between 2006-07, and again 2 to 4 in 2007-08 and 4 to 1 in 2008-09).</u> On the contrary, the other teachers have been able to remain consistent for once at least.
Jill remained consistent during 2005-07.
Ralph's performance was steady during the year 2006-07 and 2008-09.
Tina was stable during the period 2007-09.
And Sam was able to perform consistently throughout the year 2008-09.
This observation validates the point that Ed has remained most inconsistent and exhibits the most variation during this span of five-years.