A statement poem is not a genre of poetry, like narrative or lyric; it is a poem whose name comes from its content. In other words, it makes a statement rather than telling a story or presenting an image. Usually the statement is intended to be persuasive or presentational; its author uses poetry as his/her venue of expression, but has something to say beyond a poetic theme or motif.
Political statement poetry
Few political statements are poetic, but the poetic stance can add immeasurably to the impact of them. For example, June Jordan (see reference 1) in "On a New Year's Eve" speaks of things that "perish/like the children/running/hard on one-way streets" and goes on to say "I have rejected propaganda teaching me/about the beautiful/the truly rare . . . the papers preaching on . . . oil and oxygen and redwoods and evergreens . . . in short supply." Rather than make a political argument in an essay or article about children caught in poverty and crime, and worldwide damage to the eco-system, Jordan chooses to state her discontent in free verse, a far more powerful stance than mere soapbox talk.
Social statement poetry
Not all statement poetry is found on the printed page, either. Rap and slam artists are abundant in their use of musical/poetic forms to make statements about social injustice, sexuality and economic hardships. The legendary rap artist Tupac Shakur, for example (see reference 2), paved the way for statement poems by speaking of little else besides social and economic inequality in his works. Shakur realized, as do many other rap artists, that the musical venue is far more expressive than human speech; people may walk away from a speaker expressing disgust over indifference to the poor, but statements such as "long live the rose that grew from concrete when no one else cared" are far more difficult to ignore. The point is made poetically with greater impact than a mere rant could ever achieve.
Personal statement poetry
Statement poetry can be personal, while still retaining the edge and voice of a statement. Slam poet Cristin O'Keefe Aptowicz (see reference 3), in "Barfly," presents a sickened wife's hatred of her husband's drunkenness, but uses imagery for specific complaints. Her statements, which would be the cries of a shrew spoken in conversation, achieve new power through the poetic approach: "you snored so garishly . . . it was anarchy, an all-cat version of Altamont and your chokes and gurgles and snorts were the Rolling Stones . . . you left me a hot limp pickle wrapped in saran wrap next to my keyboard." The metaphors for disturbed rest, chaotic emotions and impotence are inescapable and powerful, and live far beyond the complaints that originated them.
The Poetry of Truth
Statement poets have discovered a truth that all poets innately know but do not always trust: metaphor, personification and other figurative usages in poetry make statements, just as surely as does a person standing on a street corner shouting at the rain. The difference is, the street ranter is forgotten in moments; the poetic image of the statement poem lives on, perhaps forever, in the collective mind.