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2018 School Rankings

STATE OF EDUCATION Greater

Spring 2018 Overview of Presentation

1 STATEWIDE ANALYSIS

2 REGIONAL ANALYSIS

3 STATEWIDE DISTRICT ANALYSIS

4 ANALYSIS

5 GOLD RIBBON ANALYSIS

6 HOUSTON ISD IR SCHOOLS 2 2 STATEWIDE ANALYSIS

3 C@R ranks all elementary and middle schools across three main areas and all high schools across four main areas I II III IV ELEMENTARY + MIDDLE SCHOOLS

HIGH SCHOOLS

STUDENT ACHIEVEMENT STUDENT COLLEGE ACHIEVEMENT + POVERTY GROWTH READINESS

To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit https://texasschoolguide.org/ 4 Statewide Grade Distribution of Schools by Grade Level

% of Schools Statewide Ranked…

A B C D F

ELEMENTARY 10% 27% 27% 25% 11% 4,503 schools

MIDDLE 11% 29% 30% 22% 8% 2,044 schools

HIGH 12% 27% 29% 22% 10% 1,407 schools

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 5 https://texasschoolguide.org/ Statewide Grade Distribution of Elementary Schools Over Time

% of Elementary Schools Statewide Ranked…

A B C D F

YEAR 2016 7% 21% 26% 27% 19%

2017 8% 24% 27% 27% 14%

2018 10% 27% 27% 25% 11%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 6 https://texasschoolguide.org/ Statewide Grade Distribution of Middle Schools Over Time

% of Middle Schools Statewide Ranked…

A B C D F

YEAR 2016 9% 25% 28% 27% 11%

2017 12% 29% 29% 21% 9%

2018 11% 29% 30% 22% 8%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 7 https://texasschoolguide.org/ Statewide Grade Distribution of High Schools Over Time

% of High Schools Statewide Ranked…

A B C D F

YEAR 2016 7% 24% 27% 25% 17%

2017 11% 29% 26% 21% 13%

2018 12% 27% 29% 22% 10%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 8 https://texasschoolguide.org/ Schools with mobility rates below 9% are more likely to have an “A” than those with higher mobility rates

Relationship Between Grades and Campus Mobility 0-9% mobility 9-13% mobility 13-17% mobility 17% + mobility

6% 2% 2% 11% 32% 24% A Mobility is 37% 27% defined by TEA as the % of students who are 35% enrolled at a 38% school for less B than 83% of 33% 36% the school year

C 17% 31% 19% 24% D 10% 3% 5% 9% F Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, 9 please visit https://texasschoolguide.org/ Mobility Rates in School Districts

Highest Mobility Rates Compared to the Statewide Average

Enrollm ent % Eco Dis Mobility Rate % A/B

TEXAS 5291937 59% 14% 38%

TEXAS COLLEGE PREPARATORY ACADEMIES 30394 49% 38% 30%

KILLEEN ISD 42034 55% 24% 27% Mobility is defined by EDGEWOOD ISD 10674 87% 23% 11% TEA as the % CORPUS CHRISTI ISD 36698 68% 23% 25% of students who are SPRING ISD 35041 69% 23% 8% enrolled at a school for less ALIEF ISD 46045 83% 22% 20% than 83% of JUDSON ISD 22288 64% 22% 23% the school year PHARR-SAN JUAN-ALAMO ISD 30827 88% 21 % 37%

SAN ANTONIO ISD 60706 90% 20% 6%

VICTORIA ISD 13979 66% 20% 13%

= higher than the statewide average = lower than the statewide average

10 *Includes districts with at least 10,000 students REGIONAL ANALYSIS

11 Demographics Statewide and in Major Regions

Tot al # of % in Special % Eco Dis % Asian % Black % Hispanic % White % Other St u d en t s Education

Texas 5,025,094 58% 4% 12% 53% 28% 3% 9%

Great er Hou st on Area 1,266,077 56% 7% 17% 49% 24% 3% 8%

Greater Area 1,257,461 53% 7% 18% 41 % 31 % 3% 9%

Greater Area 41 3,006 59% 2% 7% 68% 20% 3% 10%

Fort W ort h 343,71 2 56% 5% 19% 41 % 30% 4% 8%

Rio Grande Valley 342,006 86% 0% 0% 97% 2% 0% 8%

Great er Au st i n Area 336,958 44% 6% 7% 47% 37% 4% 10%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 12 https://texasschoolguide.org/ The Rio Grande Valley region has the highest number of schools with an A or B grade despite having the highest percentage of low-income students

% A and B Grades + % Economically Disadvantaged Students in Major Regions Rio Grande Valley 46% # of students: 349,555 86% North Texas 44% 54% # of students: 1,283,623 Houston 42% # of students: 1,304,060 57% Tarrant 41% # of students: 351,171 55% Austin 40% # of students: 349,276 44% Texas 38% # of students: 5,291,937 59% San Antonio 33% # of students: 444,331 59% 0% 20% 40% 60% 80% 100% % A or B Grades % Eco Dis

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 13 https://texasschoolguide.org/ Nearly one-third of high-poverty schools in the Rio Grande Valley are high performing (with an A or B grade) despite 86% of students low-income

Share of High-Performing Schools Among High- Poverty Schools in Major Regions

Rio Grande Valley 31% 86% Texas 13% 59% North Texas 11% Gold Ribbon 54% Schools are schools that have a student Houston 9% body that is at least 57% 75% economically Tarrant County 5% disadvantaged, 55% have an A or B grade, and are not Austin 4% magnet or charter 44% schools San Antonio 3% 59% 0% 20% 40% 60% 80% 100% % Gold Ribbon Schools % Eco Dis Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 14 https://texasschoolguide.org/ Comparison of Gold Ribbon Schools in Major Regions

Share of High-Performing Schools Among High- Poverty Schools in Major Regions

# of High- # of Gold Ribbon % Gold Ribbon % Economically Poverty Schools Schools Disadvantaged School Rio Grande Valley 426 134 31% 86% Gold Ribbon Schools are Texas 2,854 374 13% 59% schools that have a student body North Texas 602 65 11% 54% that is at least 75% economically disadvantaged, Greater Houston 591 55 9% 57% have an A or B grade, and are Tarrant County 157 8 5% 55% not magnet or charter schools 119 5 4% 44%

Greater San Antonio 242 8 3% 59%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 15 https://texasschoolguide.org/ STATEWIDE DISTRICT ANALYSIS

16 ISD increased the most number of schools with A or B grade catching up to Houston ISD (both with nearly 1/3 of schools with an A or B)

% A and B Grades + % Economically Disadvantaged Students in the 10 Largest School Districts in Texas (by enrollment) Katy ISD 69% + 2% since 2017 # of students: 72,026 30% Cypress-Fairbanks ISD 62% + 6% since 2017 # of students: 114,075 50% Fort Bend ISD 58% + 3% since 2017 # of students: 73,615 37% 44% North East ISD - 6% since 2017 # of students: 66,702 46% 43% Northside ISD - 4% since 2017 # of students: 105,002 50% 38% Austin ISD - 2% since 2017 # of students: 81,579 53% 33% Houston ISD + 1% since 2017 # of students: 229,399 74% 31% Dallas ISD + 10% since 2017 # of students: 154,428 88% 16% Fort Worth ISD + 4% since 2017 # of students: 85,106 76% 6% San Antonio ISD - 1% since 2017 # of students: 60,706 90% 0% 20% 40% 60% 80% 100% % A or B Grades % Eco Dis 17 Dallas ISD nearly doubled the number of high-poverty, high-performing schools (with an A or B grade) from 22 schools to 40 schools

Share of High-Performing Schools Among High-Poverty Schools in the 10 Largest School Districts in Texas (by enrollment)

20% Dallas ISD 88% + 9% since 2017 15% + 1% since 2017 Cypress-Fairbanks ISD 50% 11% Houston ISD 74% + 2% since 2017 9% Northside ISD 50% - 3% since 2017 7% Austin ISD 53% - 3% since 2017 4% Fort Worth ISD 76% + 0% since 2017 1% San Antonio ISD 90% - 3% since 2017 0% Katy ISD 30% + 0% since 2017 0% Fort Bend ISD 37% + 0% since 2017 0% North East ISD 46% + 0% since 2017 0% 20% 40% 60% 80% 100%

% A or B Grades % Eco Dis 18 Comparison of Gold Ribbon Schools in Major Regions

Share of High-Performing Schools Among High- Poverty Schools in Major Regions

% # of High- # of Gold % Gold Economically % Change Poverty Ribbon Ribbon Disadvantage Since 2017 School Schools Schools d Gold Ribbon Dallas ISD 88% 201 40 20% + 9% Schools are Cy-Fair ISD 50% 13 2 15% + 1% schools that have a student body Houston ISD 74% 196 21 11% + 2% that is at least Northside ISD 50% 22 2 9% - 3% 75% economically disadvantaged, Austin ISD 53% 56 4 7% - 3% have an A or B Fort Worth ISD 76% 85 3 4% 0% grade, and are not magnet or San Antonio ISD 90% 85 1 1% - 3% charter schools Katy ISD 30% 1 0 0% 0% Fort Bend ISD 37% 12 0 0% 0% North East ISD 46% 17 0 0% 0%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 19 https://texasschoolguide.org/ GREATER HOUSTON REGIONAL ANALYSIS

20 Greater Houston Area

• Harris County • Brazoria County • Chambers County • Fort Bend County • Galveston County • Liberty County • Montgomery County • Waller County

Home to 56% 1.2 Million 1 in 4 of students HTX students in HTX are Students in Texas low-income

21 Academic Benchmark Performance in Greater Houston

3-5th Grade Reading + Algebra I English I + Average Graduation Math EOC II EOC SAT Score Rates

GREATER 47% 41% 46% 1361 83% Meet Meet Meet Avg. Total (C@R rate) HOUSTON Grade Level Grade Level Grade Level Score

TEXAS 45% 40% 45% 1220 86% Meet Meet Meet Avg. Total (C@R rate) STATEWIDE Grade Level Grade Level Grade Level Score

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 22 https://texasschoolguide.org/ Greater Houston Grade Distribution of Schools by Grade Level

% of Schools in Greater Houston Ranked…

A B C D F

ELEMENTARY 13% 28% 27% 21% 10% 892 schools

MIDDLE 19% 26% 32% 15% 8% 328 schools

HIGH 22% 24% 21% 21% 13% 190 schools

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 23 https://texasschoolguide.org/ Comparison of A and B Schools in Major Regions

% Schools # Students Ranked A/B per 1,000 in A/B

Rio Grande Valley 46% 429

Greater North Texas Area 44% 431

Greater Houston Area 42% 444

Tarrant County 41% 413

Greater Austin Area 40% 471

Texas Statewide 38% 394

Greater San Antonio Area 33% 343

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 24 https://texasschoolguide.org/ Comparison of Gold Ribbon Schools in Major Regions

% High Poverty* # Students per 1,000 in Gold Ribbon Schools Gold Ribbon Schools

Rio Grande Valley 31% 289

Texas Statewide 13% 123

Greater North Texas Area 11% 91

Greater Houston Area 9% 83

Tarrant County 5% 40

Greater Austin Area 4% 47

Greater San Antonio Area 3% 26

*High-poverty schools defined as schools with at least 75% of students classified as economically 25 disadvantaged. Gold Ribbon schools are high-poverty schools receiving an A or B. GREATER HOUSTON DISTRICT ANALYSIS

26 School Indicator Performance in 10 Largest Districts in Greater Houston

3-5th Grade Graduation Reading + Algebra I English I+II Average Rate Enrollment % Eco Dis Math % Meets % Meets SAT Score

TEXAS 5.3 mill 59% 45% 40% 45% 1220 86% HOUSTON ISD 229,399 74% 41% 28% 35% 1278 78% CY-FAIRBANKS ISD 114,075 50% 52% 55% 59% 1477 86% FORT BEND ISD 73,615 37% 56% 52% 58% 1465 86% KATY ISD 72,026 30% 63% 62% 67% 1561 88% ALDINE ISD 59,541 86% 32% 28% 25% 1187 81% CONROE ISD 59,313 36% 60% 54% 60% 1495 81% PASADENA ISD 55,990 78% 36% 34% 34% 1290 80% KLEIN ISD 51,076 40% 53% 38% 53% 1472 85% ALIEF ISD 46,045 83% 33% 31% 31% 1289 82% CLEAR CREEK ISD 41,607 28% 57% 60% 65% 1551 86%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 27 https://texasschoolguide.org/ Comparison of A and B Schools in Largest HTX Districts Over Time

% A/B Schools by District in 2017 & 2018

-5 pts. 2017 2018

79% +1 pts. Most large school districts in -1 pts. 74% Greater Houston improved between +4 pts. pts. 69% +6 2017 and 2018, increasing the share 69% 68% 68% +3 pts. 64% 62% of schools receiving an A or B. 60% 58% 56% 55%

+1 pts. +6 pts. 32% 33% No change 26%

20% 20% 20% +3 pts.

5% 2017 2018 2%

CLEAR CREEK CONROE ISD KATY ISD KLEIN ISD CY-FAIR ISD FORT BEND ISD HOUSTON ISD PASADENA ISD ALIEF ISD ALDINE ISD ISD

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 28 https://texasschoolguide.org/ Comparison of Gold Ribbon Schools in Largest HTX Districts Over Time

% Gold Ribbon Schools by District in 2017 & 2018

2017 2018

-11 pts. Half of large school districts in Greater +13 pts. Houston saw increases in high- 20% 20% performing, high-poverty schools. +1 pts. +5 pts. Most other districts with fewer high- 15% 16% 14% poverty schools saw declines or no +3 pts. change in Gold Ribbon schools

11% 11% 9% 8% 7% +2 pts.

4% No change No change No change 2017 2018 2% 0% 0% 0% 0% 0% 0% * 0% CONROE ISD CY-FAIR ISD ALIEF ISD HOUSTON ISD PASADENA ISD ALDINE ISD FORT BEND ISD KATY ISD KLEIN ISD CLEAR CREEK n=11 n=13 n=38 n=196 n=46 n=56 n=12 n=1 n=6 ISD n=1 Number of schools with at least *No high-poverty 75% low-income students in 2018 29 schools in 2017 School Indicator Performance in 6 Largest Charter Districts in Greater Houston

3-5th Grade Graduation Reading + Algebra I English I+II Average Rate Enrollment % Eco Dis Math % Meets % Meets SAT Score

TEXAS 5.3 mill 59% 45% 40% 45% 1220 86%

YES PREP 16,952 86% -- 67% 62% 1341 92%

KIPP CHARTER 12,481 91% 53% 25% 52% 1324 94%

HARMONY SCH. OF EXCELLENCE 7,602 56% 49% 66% 63% 1506 90%

HARMONY SCH. OF SCIENCE 6,021 43% 67% 84% 80% 1610 94%

HOUSTON GATEWAY ACADEMY 5,271 92% 72% 90% 67% 1224 83%

HARMONY SCIENCE ACADEMY 5,071 74% 40% 62% 51% 1333 95%

Source: CHILDREN AT RISK 2018 school rankings. To access the full CHILDREN AT RISK 2018 school rankings methodology, please visit 30 https://texasschoolguide.org/ Comparison of A and B Schools in HTX Charter Districts Over Time

% A/B Schools by Charter District in 2017 & 2018

2017 2018 +3 pts. 100% -13 pts. 89% 86% 80%

-1 pts. 67% No change Houston Gateway Academy +5 pts. was not ranked in 2017; in 59% 58% 56% 56% 2018, all 7 schools received 50% an A or B 45%

* 2017 2018 HARMONY SCHOOL OF HARMONY SCHOOL OF YES PREP PUBLIC HARMONY SCIENCE KIPP INC CHARTER HOUSTON GATEWAY SCIENCE - HOUSTON EXCELLENCE SCHOOLS INC ACADEMY ACADEMY INC n=9 n=12 n=19 n=9 n=22 n=7

Number of schools in 2018; Only charters with at least 5,000 31 students are shown. HARRIS COUNTY GOLD RIBBON ANALYSIS

32 Harris County Neighborhoods

Kinder Institute’s Community Tabulation Areas (CTAs)

• 143 CTAs in Harris County • Based on Census tracts • Designed to represent real communities • Boundaries drawn based on community feedback • For more info: http://www.datahouston.org/CTA_Documentation.pdf

33 5 Indicators Shown in Upcoming Maps:

% of children in poverty

% without a high school diploma

% with bachelor’s degree or higher

% Hispanic/Latino and African American

34 5 Gold Ribbon Elementary Schools Across Harris County By Levels of Poverty

% Children in Poverty

Neighborhood % Children in Type Poverty, 2015 Gold Ribbon 35%

Harris County 27%

Note: Neighborhoods represented by Kinder Institute’s Community Tabulated Areas. For more info: http://www.datahouston.org/CTA_Documentation.pdf 35 6 Gold Ribbon Elementary Schools Across Harris County By Education

% Without High School Diploma

Neighborhood % without HS Type diploma, 2015 Gold Ribbon 32%

Harris County 20%

Note: Neighborhoods represented by Kinder Institute’s Community Tabulated Areas. For more info: http://www.datahouston.org/CTA_Documentation.pdf 36 7 Gold Ribbon Elementary Schools Across Harris County By Education

% with Bachelor’s Degree (over 25)

Neighborhood % Bachelor’s Type Degree, 2015 Gold Ribbon 17%

Harris County 29%

Note: Neighborhoods represented by Kinder Institute’s Community Tabulated Areas. For more info: http://www.datahouston.org/CTA_Documentation.pdf 37 8 Gold Ribbon Elementary Schools Across Harris County By Race-Ethnicity

% Hispanic or Latino

Neighborhood % Hispanic or Type Latino, 2015 Gold Ribbon 56%

Harris County 42%

Note: Neighborhoods represented by Kinder Institute’s Community Tabulated Areas. For more info: http://www.datahouston.org/CTA_Documentation.pdf 38 9 Gold Ribbon Elementary Schools Across Harris County By Race-Ethnicity

% African American

Neighborhood % African Type American, 2015 Gold Ribbon 19%

Harris County 18%

Note: Neighborhoods represented by Kinder Institute’s Community Tabulated Areas. For more info: http://www.datahouston.org/CTA_Documentation.pdf 39 10 ANALYSIS OF HOUSTON ISD IR SCHOOLS

40 Houston ISD Schools at Risk (IR for 4 Years) Demographic Characteristics

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years 41 Houston ISD Schools at Risk (IR for 4 Years) Elementary Schools

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years 42 Houston ISD Schools at Risk (IR for 4 Years) Middle Schools

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years 43 Houston ISD Schools at Risk (IR for 4 Years) High Schools

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years 44 Houston ISD Schools feeding into Kashmere HS (IR for 4 Years) Kashmere HS Feeder Pattern

At 2 out of 4 of the elementary schools feeding into Kashmere HS in 2017, fewer than half of students answered 50% of questions correctly on the 3rd grade reading STAAR exam.

In 2015, all 4 schools fell into that category.

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years

45 Houston ISD Schools feeding into Worthing HS (IR for 4 Years) Worthing HS Feeder Pattern

At 5 out of 6 of the elementary schools feeding into Worthing HS in 2017, fewer than half of students answered 50% of questions correctly on the 3rd grade reading STAAR exam

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years

46 Houston ISD Schools feeding into Wheatley HS (IR for 4 Years) Wheatley HS Feeder Pattern

At 2 out of 8 of the elementary schools feeding into Wheatley HS in 2017, fewer than half of students answered 50% of questions correctly on the 3rd grade reading STAAR exam.

In 2015, 6 out of 8 schools fell into that category.

Source: Texas Education Agency’s STAAR aggregate data for 2014-15 through 2016-17 schools years

47 Houston ISD Schools at Risk Infant Mortality by Feeder Pattern

Infant deaths per thousand, 2015 * Kashmere 12.4 North Forest 12.3 Scarborough 8.6 Yates 8.2 Washington 7.8 Northside 7.7 Differences in academic performance Chavez 7.1 Furr 7.0 across schools also reflect * Worthing 6.8 environmental stressors stretching Austin 6.7 Westbury 6.7 back to early childhood. Waltrip 6.3 Houston 6.0 For instance, infant mortality is Milby 5.9 Charter 5.9 particularly high in the neighborhoods Sharpstown 5.7 in the Kashmere feeder pattern. Madison 5.6 Sterling 5.6 Heights 5.4 Bellaire 5.3 * Wheatley 5.3 Lamar 4.7 Wisdom 4.1 Westside 2.6 Source: Lakey et al (2018) estimates of infant mortality by zip code. Rate represents average across zip codes for schools in feeder pattern. 48 APPENDIX

49 Change in A and B Schools in 10 Largest Districts Over Time

# Campuses # A/B 2018 % A/B 2018 # A/B 2017 % A/B 2017 % Change in A/B*

DALLAS ISD 225 69 31% 47 21% +47%

FORT WORTH ISD 124 20 16% 15 12% +33%

CY-FAIR ISD 82 51 62% 46 56% +11%

KATY ISD 59 41 69% 38 68% +8%

FORT BEND ISD 72 42 58% 39 55% +8%

HOUSTON ISD 273 89 33% 87 32% +2%

SAN ANTONIO ISD 94 6 6% 6 7% 0%

AUSTIN ISD 113 43 38% 45 40% -4%

NORTHSIDE ISD 111 48 43% 51 47% -6%

NORTH EAST ISD 68 30 44% 34 50% -12%

*% change was calculated by subtracting the number of A or B rated schools in 2018 minus the number of A or B rated schools in 2017 and 50 dividing the difference over the original number of A or B rated schools in 2017 Change in Gold Ribbon Schools in 10 Largest Districts Over Time

% Change in Gold # Campuses # GR 2018 % GR 2018 # GR 2017 % GR 2017 Ribbon* DALLAS ISD 225 40 20% 22 11% + 82%

HOUSTON ISD 273 21 11% 16 8% +31%

CY-FAIR ISD 82 2 15% 2 14% 0%

FORT WORTH ISD 124 3 4% 3 3% 0%

FORT BEND ISD 72 0 0% 0 0% 0%

KATY ISD 59 0 0% 0 0% 0%

NORTH EAST ISD 68 0 0% 0 0% 0%

NORTHSIDE ISD 111 2 9% 3 12% -33%

AUSTIN ISD 113 4 7% 6 10% -33%

SAN ANTONIO ISD 94 0 0% 3 4% -100%

*% change was calculated by subtracting the number of A or B rated schools in 2018 minus the number of A or B rated schools in 2017 and 51 dividing the difference over the original number of A or B rated schools in 2017