You've received a lot of great advice and information already.
I share your concern regarding test score data and reading group placement information not being shared on a timely basis. That being said, substitute teachers, even long-term subs, may have limited decision-making authority. Because you mention that this sub has had several assignments with the school, your paths may cross again, as she may be likely to sub again or even be hired in a regular teaching position.
You may already have explored the MAP test website (NWEA.org), and may have read their articles about sharing test results, using score ranges, utilizing three pieces of data (triangulation) to make placement decisions etc (to navigate through their website to this information, click on "support", then "article", sharing-results-students). The RIT score charts also provide interesting background information. The ideas gleaned from reading the test company's website may be helpful to keep in the back of one's mind when meeting with DD's teacher after she returns from maternity leave.
Some agenda items to guide a meeting discussion might be those which help you learn:
1- What data is being used to determine DD's reading placement?
2- Relative strengths and weaknesses? What identified skills to work on?
3- How is comprehension being assessed?
* 4- How a child qualifies for placement in the next higher reading group?
You may wish to keep a list of books your DD reads at home, noting their reading level, and date. This may be helpful for future advocacy.
(*In some cases, such as F&P, a teacher may be able to share a comprehension rubric, the results of which are separate from the letter score. Further conversation may lead to the Continuum of Literacy Learning, a book which the teacher may have received included in the professional framework, part of the benchmark assessment system.)Good luck with this.
ETA: link to one of the threads which previously discussed
DRA assessments.
