In 1998, BBRC explained its approach to the assessment of single-observer records. The committee explained that while it understood that geographical and social circumstances make it likely that some people are more likely to find rare birds on their own, it is "very cautious about observers with a high proportion of single-observer records" and that its policy is to watch patterns closely and review those observers' past records on a regular basis. This approach has attracted criticism. Former BBRC chairman Ian Wallace and others have written about the subject in "Birdwatch" magazine. Wallace believes that the committee has a blacklist of observers, from whom it automatically rejects records unless there are other observers able to corroborate the sighting. He mentions two specific observers, both of whom live in remote parts of northern Scotland. Ken Shaw, a former BBRC member, has claimed that BBRC would not accept a single-observer record of a species new to Britain without photographic evidence, regardless of the track record of the observer. Graham Bell, another former member, writing in response to Shaw's article, has accused the committee of adopted unfounded suspicions, arguing that just because a competent observer moves to an underwatched part of the country, their abilities do not change. One of the observers who Wallace claimed was blacklisted, Alan Vittery, also contributed to the debate, stating that he had been informed by the BBRC that they would not consider any single-observer record he submitted, unless supported by a photograph. Vittery contrasted the BBRC's attitude with that of other national rarities committees, arguing that the result of the approach is to distort rarity statistics. Vittery invited the BBRC to reply in public, but this request was declined.