While admitting to the roles they played in cheating, educators at every level said they felt unrelenting pressure to meet what they considered unrealistic targets on standardized tests imposed by Hall. They said they also felt pressure to remain silent about their actions in order to keep their jobs.

GUILTY PLEAS SO FAR

Top administrators

Millicent Few, former APS human resources director. Pleaded guilty Monday to misdemeanor malfeasance in office. Few is expected to testify that Hall ordered the destruction of internal investigative reports that found "a substantial likelihood that cheating occurred" in 2008 when students took standardized tests at Deerwood Academy, prosecutors said. Sentence: One year on probation, 250 hours of community service, $800 in restitution.

Principals

Lucious Brown, former principal of Kennedy Middle School. Brown pleaded guilty Jan. 17 to interfering with government property. He admitted erasing students' answers and changing them from wrong to right in 2008 and 2009. He is expected to testify against Sharon Davis-Williams, a top administrator whose office was at Kennedy. Sentence: Two years on probation, 1,000 hours of community service, return $1,000 in bonus pay.

Clarietta Davis, former principal of Venetian Hills Elementary School. Davis pleaded guilty Jan. 6 to one felony count of false statements. She admitted to changing answers from wrong to right on standardized tests in 2007 and 2008. Prosecutors said Davis often met with Hall and Davis-Williams and went over data that showed many Venetian Hills students were testing below their grade levels. In those meetings, Hall applied constant pressure on Davis to make sure her students met testing goals. Sentence: Two years on probation, 1,000 hours community service, return $500 in bonus money.

Armstead Salters, former principal of Gideons Elementary School. Salters pleaded guilty Dec. 19 to a felony count of making false statements and writings since he signed off on tests taken by his students. Salters disclosed to prosecutors how he coordinated test cheating and explained why he did it. Gideons, located in southwest Atlanta, had a challenging, transient student population after nearby housing projects closed in the early 2000s. Its students performed slightly below average in reading, language arts and math. Hall made it clear she would fire teachers and principals who did not get good results on test scores, he said. Sentence: Two years on probation, 1,000 hours of community service, return $2,000 in bonus pay.

Christopher Waller, former principal of Parks Middle School. Waller pleaded guilty Friday to a felony count of making false statements. Parks had some of the most egregious instances of cheating, according to a 2011 state investigative report, and Waller went to great lengths to to cover it up, the report said. He is expected to implicate Hall and former area superintendent Michael Pitts in his testimony. Sentence: Five years on probation, 1,000 hours of community service, $50,000 in fines and restitution.

Assistant principals, testing coordinators

Gregory Reid, former assistant principal of Parks Middle School. Reid pleaded guilty Dec. 16 to two counts of obstruction. His decision to testify for the prosecution likely influenced Waller's move to enter a guilty plea. Sentence: Two years on probation, 500 hours of community service, return $5,000 in bonus money.

Francis Mack, former testing coordinator at D.H. Stanton Elementary School. Mack pleaded guilty Dec. 20 to obstruction. Prosecutors said Mack did not participate in test cheating but had previously been told about testing irregularities and did not disclose that information to investigators. Sentence: one year on probation, 250 hours of community service.

Sheridan Rogers, former testing coordinator at Gideons Elementary School. Rogers pleaded guilty Dec. 20 to obstruction. She admitted to following orders from her principal, Salters, to give Gideons' teachers access to their tests and answer sheets. This allowed teachers to change wrong answers to right ones. Sentence: one year on probation, 250 hours community service, return $1,000 in bonus money.

Lera Middlebrooks, former testing coordinator at Dunbar Elementary School. Middlebrooks pleaded guilty Dec. 18 to one misdemeanor count of obstruction. She admitted to giving teachers answer sheets for standardized tests after students had taken the tests and said she believed the teachers used the sheets to change incorrect answers. Sentence: One year on probation.

Tameka Goodson, former school improvement specialist at Kennedy Middle School. Goodson pleaded guilty Dec. 20 to obstruction. Goodson admitted to changing answers on student standardized tests in 2008 along with secretary Carol Dennis under the director of their principal, Brown. Sentence: one year on probation, 250 hours community service, return $1,000 in bonus money.

Sandra Ward, testing coordinator at Parks Middle School. Ward pleaded guilty Friday to one misdemeanor count of obstruction. She is expected to implicate Hall and Pitts in her testimony. Sentence: One year on probation, 250 hours of community service, return $5,000 in bonus money.

Teachers

Starlette Mitchell, former teacher at Parks Middle School. Mitchell pleaded guilty Jan. 6 to one misdemeanor count of obstruction. Sentence: one year on probation, 250 hours of community service, return $3,000 in bonus money.

Kimberly Oden, former teacher at Parks Middle School. Oden pleaded guilty Jan. 6 to one misdemeanor count of obstruction. Sentence: one year on probation, 250 hours of community service.

Derrick Broadwater, teacher at Dobbs Elementary School. Broadwater pleaded guilty Jan. 6 to one misdemeanor count of obstruction. Sentence: one year on probation, 350 hours of community service, return $2,000 in bonus money.

Shayla Smith, teacher at Dobbs Elementary School. Smith pleaded guilty to a single misdemeanor count of obstruction. She is expected to testify against others at her school, including her former principal, Dana Evans, and area superintendent Pitts. Sentence: one year on probation, 250 hours of community service.

Gloria Ivey, former teacher at Dunbar Elementary School. Ivey pleaded guilty Jan. 6 to one misdemeanor count of obstruction. Ivey said she succumbed to pressure placed on her by administrators who expected her students to meet unrealistic test goals. She admitted to admonishing students to rethink incorrect test answers as she walked around her class and pointing to the correct answers in some cases. Sentence: one year on probation, 250 hours of community service.

Lisa Terry, former teacher at Humphries Elementary School. Terry pleaded guilty Nov. 20 to a misdemeanor charge of obstruction, the first educator to enter a guilty plea. Terry admitted she allowed students to go back and change their answers on the 2009 Criterion-Referenced Competency Tests. Sentence: one year on probation, 250 hours of community service.

Ingrid Abella-Sly, former teacher at Humphries Elementary School. Abella-Sly pleaded guilty Dec. 13 to a misdemeanor obstruction charge and admitted she gave students answers on standardized tests. Sentence: One year on probation, 250 hours of community service, return $500 in bonus pay.

Wendy Ahmed, former teacher at Humphries Elementary School. Ahmed pleaded guilty Dec.19 to a misdemeanor count of obstruction. She admitted telling her students the correct answers while they took the 2009 test. Sentence: One year on probation, 250 hours of community service, return $500 in bonus money.

Sheila Evans, former teacher at Benteen Elementary School. Evans pleaded guilty Dec. 16 to one misdemeanor count of obstruction. Sentence: One year on probation, 250 hours of community service.

Secretary

Carol Dennis, secretary at Kennedy Middle School. Dennis pleaded guilty Jan. 6 to one misdemeanor count of obstruction. She said she corrected student answers on the 2008 and 2009 CRCTs at Brown's request. Sentence: one year on probation, 250 hours of community service.

13 defendants remain and are expected to stand trial:

Beverly Hall, superintendent

Tamara Cotman, area superintendent

Michael Pitts, area superintendent

Sharon Davis-Williams, area superintendent

Dana Evans, principal of Dobbs Elementary

Tabeeka Jordan, assistant principal of Deerwood Academy

Donald Bullock, testing coordinator at Usher/Collier Heights Elementary

Theresia Copeland, testing coordinator at Benteen Elementary

Diane Buckner-Webb, teacher at Dunbar Elementary

Pamela Cleveland, teacher at Dunbar Elementary

Dessa Curb, teacher at Dobbs Elementary

Shani Robinson, teacher at Dunbar Elementary

Angela Williamson, teacher at Dobbs Elementary

DIGGING DEEPER: THE STORY SO FAR

The Atlanta Journal-Constitution first investigated improbable improvements on standardized tests in 2008 and then conducted a computer analysis of schools with unusual changes in test scores in 2009.

A state investigation ordered by Gov. Sonny Perdue concluded in July 2011 that 185 APS teachers and administrators participated in cheating on the 2009 CRCTs. Investigators found suspicious rates of changed answers on standardized tests, and they said in their 413-page report that there was evidence of cheating at 44 Atlanta schools. The investigation formed the basis for the criminal charges brought against the educators March 29, 2013.

WHERE THE PROSECUTION STANDS

The case against the remaining defendants, especially Hall, likely will hinge on the 21 former school personnel who will testify for the prosecution. Here’s what prosecutors likely will want to accomplish:

Tie the top to the bottom: Hall and other top administrators are charged with racketeering, as the indictment says they pressured those under them to cheat. To prove that, prosecutors will need witnesses to explain that pressure and tie it to Hall and other executives.

Show a pattern of abuse: Prosecutors will want to show that test cheating was encouraged and tolerated across the district.

Look, sound credible: Like all trials, witnesses will have to come off as credible to jurors.

WHAT THE DEFENDANTS WILL FACE

If convicted of false statements and writings; false swearing; theft by taking; and influencing witnesses charges, the sentence ranges are one to five years in prison. A conviction on racketeering carries a sentence of five to 20 years.

WHAT’S NEXT

Now that the judge’s deadline has passed for plea deals, a racketeering and conspiracy trial is expected to begin in May with 13 defendants.