The GREEN set of Developing Decoders follow the UFLIs program's skill progression. The following is a list of the skills in order with the number of book titles:

The GREEN set of Developing Decoders follow the UFLIs program's skill progression. The following is a list of the skills in order with the number of book titles in parentheses: alphabet (one book with a collection of 28 passages), alphabet review and longer words (32 titles), digraphs (24 titles), VCe (20 titles), reading longer words (14 titles), ending spelling patterns (16 titles), r-controlled vowels (14 titles), long vowel teams (10 titles), other vowel teams (14 titles), diphthongs (6 titles), silent letters (8 titles), suffixes and prefixes (16 titles), suffix spelling changes (8 titles), low-frequency spellings (18 titles), additional affixes (20 titles).

The ORANGE set of Developing Decoders follow a skill progression based on syllable type. The first set includes 15 books and covers VC and CVC syllable types along with blends and digraphs. The second set includes 10 books and covers the VCE syllable type. The third set includes 15 books and covers the CV and C+LE syllable types along with other word endings. The fourth set includes 10 books and covers r-controlled vowels. The fifth set includes 15 books and covers vowel teams and silent letters.