<![CDATA[This research is that aims to produce products in the form of teaching materials based ATM, and to know the effectiveness of application of teaching materials products based on ATM on the concept of circle material. The stages of Research Development were, preliminary (preparation includes preliminary study and instructional design), and formative test (self evaluation, expert review, one to one, small group, field test). The subjects of this research are students of MTsN 1 Lampung Selatan in academic Year 2016/2017 and several expert at every stage of development. The research data was obtained through concept comprehension concept test. The experts review shows that ATM based teaching materials have satisfied of standart the content, media, and language and included good category. The results of data analysis on the field test shows that there is an increasing in the ability to understanding the students concepts after given an ATM based teaching materials with quite category.Penelitian dan pengembangan yang bertujuan untuk menghasilkan produk berupa bahan ajar berbasis ATM, dan mengetahui efektivitas penerapan produk bahan ajar berbasis ATM pada konsep materi lingkaran. Tahap-tahap penelitian ini, yaitu preliminary (meliputi studi pendahuluan dan pendesainan bahan ajar), dan uji formatif (evaluasi diri, uji ahli, uji perorangan, uji kelompok kecil, dan uji terbatas). Subjek penelitian pengembangan ini adalah siswa MTsN 1 Lampung Selatan Tahun Pelajaran 2016/2017 dan beberapa ahli. Data penelitian diperoleh melalui tes kemampuan pemahaman konsep. Hasil validasi ahli menunjukkan bahwa bahan ajar berbasis ATM telah memenuhi standar kelayakan isi, media, dan bahasa dengan kategori baik. Hasil analisis data pada uji terbatas menunjukkan bahwa terjadi peningkatan kemampuan pemahaman konsep siswa setelah diberikan bahan ajar berbasis ATM dengan kategori cukup efektif.Kata kunci : bahan ajar berbasis ATM, pemahaman konsep, lingkaran]]>
