New Criticism involves examining a poem's "technical elements, textual patterns, and incongruities" (Leitch 2001) with a kind of scientific rigor and precision. From I. A. Richards' "The Principles of Literary Criticism" and "Practical Criticism", Brooks formulated guidelines for interpreting poetry (Leitch 2001). Brooks formulated these guidelines in reaction to ornamentalist theories of poetry, to the common practice of critics going outside the poem (to historical or biographical contexts), and his and Warren's frustration with trying to teach college students to analyze poetry and literature (Leitch 2001).