More than 60 Texas school districts have approved district of innovation, or DOI, plans in the two years since state lawmakers passed legislation creating the new system, which allows districts to exempt themselves from portions of the Texas Education Code.

Together, those DOI plans identify more than 50 sections of the state’s education code as targets for exemption, according to a Community Impact Newspaper analysis.

Districts that have sought to attain DOI designations have lauded the chance for more flexibility in hiring and scheduling practices. But critics such as the Texas State Teachers Association have criticized the DOI concept as too far-reaching.

Here are the Texas school districts that have approved DOI plans:

A district can become a DOI only after it develops a local innovation plan with public input and approval from an elected district-level committee and the school board. The TEA does not have authority over a DOI plan's approval, but the agency does retain the right to investigate plans that claim unallowable exemptions.

The exemption most sought by DOI districts involves a section of the code that mandates the first day of classroom instruction each school year, which typically cannot begin before the fourth Monday in August, according to the analysis.

Here are the most popular DOI exemptions:

Top 20 DOI exemptions Data current as of Jan. 10, 2017.[/caption]

1. First Day of Instruction (Texas Education Code 25.0811)
Mandates the uniform start date cannot be before fourth Monday in August.

2. Teacher certification (21.003)
Requires teachers and education professionals to hold appropriate certification (some exemptions allowed).

3. Class size limit (25.112)
Caps kindergarten through fourth-grade classes at 22 students.

4. Class size notification (25.113)
Compels districts to notify parents of class-size exemptions.

5. Minimum minutes of instruction (25.081)
Requires districts to provide at least 75,600 minutes, or 180 seven-hour days, of annual classroom instruction.

6. Minimum attendance for class credit or final grade (25.092)
Requires students attend at least 90 percent of a class to receive credit.

7. Student-to-teacher ratios (25.111)
Sets ratio of one teacher for every 20 students.

8. Last day of school year (25.0812)
Mandates last day of school cannot be before May 15.

9. Local role in teacher evaluations (21.352)
Sets criteria to evaluate teachers.

10. Teacher certification records (21.053)
Requires teachers file certification before their contracts begin.

11. Certification notification (21.057)
Compels districts with uncertified teachers to notify parents.

12. Teacher training (21.044)
Sets training requirements for teaching certificates.

13. Probationary contracts (21.102b)
Limits probationary teacher contracts to one school year.

14. Length of school day (25.082)
Requires school days to be at least seven hours long, including recesses.

15. Teaching permits (21.055)
Offers provisions for districts to hire teachers without certification.

16. Student discipline (37.0012)
Requires school campuses to designate a campus behavior coordinator.

17. Teacher appraisal (21.203)
Requires written evaluations of teachers at regular intervals.

18. Teacher contract lengths (21.401)
Sets minimum teacher contract length at 10 months.

19. Teacher contracts (21.002)
Defines educators’ contracts as probationary, continuing or term-based.

20. Planning and preparation time (21.404)
Gives teachers at least 450 minutes every two weeks for class planning and preparation.

Follow for more analysis later this week.