The Denver school board on Thursday night unanimously renewed agreements with 16 of the district’s charter schools. The lengths of those renewals, however, varied from one year to five years — and signaled the board’s confidence in the schools to deliver a quality education.

The board also accepted Roots Elementary’s decision to close and surrender its charter at the end of this school year. The Park Hill school is facing low enrollment and high costs.

Denver Public Schools is a charter-friendly school district that has for years shared tax revenue and school buildings with its 60 publicly funded, independently operated charter schools. The schools are controversial, though, with opponents viewing them as privatizing public education.

Every charter school in Denver has an agreement with the district that spells out how long it’s allowed to operate. To continue running after that time period, the charter school must seek renewal. The arrangement is part of the deal for charters: They get the flexibility to operate independently, but they must periodically prove to the district that they’re doing a good job.

The school board relies on one set of recommendations from Denver Public Schools staff and a second set of recommendations from a districtwide parent committee in deciding how long a leash to give each charter school. The district staff and the parents on the committee consider factors such as test scores, school culture, financial viability, and the strength of a school’s leaders when making their recommendations.

They also consider a school’s rating on Denver Public Schools’ color-coded scale based largely on academic factors. The School Performance Framework, or SPF, labels schools either blue, green, yellow, orange, or red. Blue means a school has a distinguished academic record, while red means a school is not meeting the district’s expectations.

The staff recommended the school board renew the charters of all 16 schools that applied. Two other charter schools — DSST: Cole Middle School and Compass Academy — are also up for renewal this year. But because they earned the district’s lowest rating, they must go through a separate process in which they will present a detailed improvement plan. Their renewals will depend on the strength of their plans, which is why they weren’t included in this batch.

The board approved the 16 renewals Thursday without discussion. All of the new terms begin next school year. Here’s the rundown:

STRIVE Prep Federal, a middle school in southwest Denver
Year opened: 2006
School rating: Green
Renewal: Five years

DSST: Green Valley Ranch High School, a high school in far northeast Denver
Year opened: 2011
School rating: Green
Renewal: Five years

Rocky Mountain Prep Creekside, an elementary school in southeast Denver
Year opened: 2012
School rating: Green
Renewal: Five years

DSST: College View High School, a high school in southwest Denver
Year opened: 2015
School rating: Green
Renewal: Three years, with a possible two-year extension

KIPP Northeast Denver Leadership Academy, a high school in far northeast Denver
Year opened: 2015
School rating: Blue
Renewal: Three years, with a possible two-year extension

KIPP Northeast Elementary School, an elementary school in far northeast Denver
Year opened: 2015
School rating: Yellow
Renewal: Two years, with a possible three-year extension

Rocky Mountain Prep Southwest, an elementary school in southwest Denver
Year opened: 2015
School rating: Yellow
Renewal: Two years, with a possible three-year extension

Wyatt Academy, an elementary school in northeast Denver
Year opened: 2003
School rating: Yellow
Renewal: Two years, with a possible two-year extension

KIPP Northeast Denver Middle School, a middle school in far northeast Denver
Year opened: 2011
School rating: Yellow
Renewal: Two years, with a possible two-year extension

Downtown Denver Expeditionary School, an elementary school in central Denver
Year opened: 2013
School rating: Yellow
Renewal: Two years, with a possible two-year extension

Denver Justice High School, an alternative high school for at-risk students in central Denver
Year opened: 2009
School rating: Yellow
Renewal: Two years, with a possible one-year extension

REACH Charter School, an elementary school in central Denver
Year opened: 2015
School rating: Yellow
Renewal: Two years, with a possible one-year extension

Monarch Montessori, an elementary school in far northeast Denver
Year opened: 2012
School rating: Orange
Renewal: One year, with a possible two-year extension

STRIVE Prep SMART, a high school in southwest Denver
Year opened: 2012
School rating: Orange
Renewal: One year, with a possible two-year extension

Academy of Urban Learning, an alternative high school for at-risk students in northwest Denver
Year opened: 2005
School rating: Red
Renewal: One year, with a possible one-year extension

Rise Up Community School, an alternative high school for at-risk students in northeast Denver
Year opened: 2015
School rating: Red
Renewal: One year