There has been some concern about the impact of predatory publishers on scientific research for some time. Recently, publishers that might previously have been considered `predatory' have established their bona fides, at least to the extent that they are included in citation impact scores such as the field-weighted citation impact (FWCI). These are sometimes called `grey' publishers (MDPI, Frontiers, Hindawi). In this paper, we show that the citation landscape for these grey publications is significantly different from the mainstream landscape and that affording publications in these venues the same status as publications in mainstream journals may significantly distort metrics such as the FWCI.

翻译：长期以来，科学界对掠夺性出版商对科研工作的影响存在一定担忧。近期，一些以往可能被视为"掠夺性"的出版商已确立其学术信誉，至少已获得纳入引文影响力指标（如领域加权引文影响力指数FWCI）的资格。这类出版商有时被称为"灰色"出版商（如MDPI、Frontiers、Hindawi）。本文研究表明，这些灰色出版物的引文分布格局与主流出版物存在显著差异，若将其与主流期刊出版物置于同等地位，可能会严重扭曲FWCI等计量指标。