DAAD says applications are reviewed by an independent selection committee of specialist scientists. The criteria include academic qualification, academic achievements, grade development, academic progress, language knowledge, and scholarly achievements such as publications, lectures, or conference papers where applicable. Applicants should present this evidence clearly instead of hiding it inside long paragraphs.
The second major criterion is the quality of the research project. This includes originality, topicality, relevance, preparation, choice of host institution, first contacts, feasibility, and consistency of the work schedule. In practice, this means the proposal, host letter, schedule, and motivation letter should tell the same story. If the proposal says the project needs a specific method but the host letter never mentions it, reviewers may doubt the fit.
The third criterion is applicant potential. DAAD considers career prospects, the significance of the project and stay in Germany for academic, professional, and personal development, motivation for Germany, German language skills if different from the working language, and non-study-related activities such as civic engagement. The motivation letter should therefore be more than praise for Germany. It should explain why this stay is the right next move for the applicant and for the research.