THEATRE / The Fringe: Taken down and used in evidence: Sarah Hemming on a spate of docudramas, including Sticks and Stones, The Secret of the White Rose and Letters Home

Say one morning an incident takes place outside your front door and you feel compelled to write a drama about it. Would you repeat verbatim everyone's point of view? Mix true statements with imagined dialogue? Or dramatise the incident and characterise the people? How much would you shape your material, how truthful could you be?

Documentary drama is a fascinating and pitfall-ridden genre, and Anna Deveare Smith's show Fires in the Mirror at the Royal Court (reviewed last week by Paul Taylor) has given a new slant on how to handle it. For her solo show about the riots in Crown Heights, Brooklyn, in 1991, Deavere Smith recorded testimonies and opinions about the events. She not only reiterates these viewpoints, but impersonates the people who made them. This has an interesting effect: the same filter (her ability to act) is applied to everyone, and her very skill at playing chameleon reminds you the whole time that this is acting - it keeps you alert. Moreover, she reproduces not just what her witnesses say, but their struggle to find the right words. The show explores the difficulty of describing an event and its import. It stands in marked contrast to three other shows this week, each of which has a documentary element, each of which uses a different style, with strengths and limitations.

Sticks and Stones is a campaigning piece based on interviews, which mixes real statements with imagined situations. Directed by Lyall Watson, it is fired by a definite intent: to draw attention to the difficulties of parents of children with special needs (the performance I saw was, enterprisingly, staged in the House of Commons). Though it centres on the life of one - fictitious - child, the show frequently broadens out to scenes portraying the frustrations of parents who, applying for help, meet a jungle of bureaucracy. The show is moving and angering, and the true statements it incorporates from parents are often painfully honest: 'Four years ago I wanted him dead, but that was a lifetime ago.' The problem is that other characters - doctors, relatives - are horribly stereotyped. The combination of true statement and caricature is detrimental to the message.

The Secret of the White Rose (Arts Threshold, W2) is a freely imagined drama based on research about a group of wartime students in Munich who printed an underground publication that denounced the Fuhrer. The drawback with the author and director Jack Klaff's show is not knowing where reportage ceases and dramatisation begins. That said, Klaff tells the story with great verve and sympathy, tracing the lives of the ringleaders (Hans Scholl and his sister Sophie) until their executions. It is a pacey, no-nonsense production full of fervent yet disciplined performances.

Rosa Leiman Goldemberg's Letters Home, by contrast (Lyric Studio, W6), is purely documentary, yet it uses only one source, tracing Sylvia Plath's life through her letters to her mother. Sylvia (Daryl Back) reads from her letters while her mother (Hildegard Neil) fills in the gaps. This gives a compressed and very vivid journey through Plath's changing psychological state. It makes for rather arid theatre though - you have two women on stage who never address one other directly; this is one play where you long for a little dramatic licence and conjectured dialogue.

'Sticks and Stones' is touring (0831-168196); 'The Secret of the White Rose' (071-262 1629) and 'Letters Home' (081-741 8701) run to 10 April.