Those that remain for post-16 study are still far less likely to complete their final studies than students in other types of education, the report said.
Previously high attaining students at UTCs - first introduced by the government in 2010 to focus on technical education - are making over a grade’s less progress than peers in all state-funded schools, the report said.
There are currently 50 UTCs open in England - with 10 having closed, announced closure, or converted into a different institution type.
Many of those which remain open are struggling with student numbers and the report found that only a third of students are enrolled in one UTC.
The EPI suggested changing the admissions age for UTCs to age 16 to 18 to overcome the struggle with admissions at the age of 14.
With poor levels of progress and retention, it is not clear that students are benefiting from a 14-19 education, it said.