What is the effect of neutral documents in the validation queue on Precision?

Neutral documents in the validation queue have no effect on Precision because Precision is defined as the ratio of relevant documents retrieved to the total number of documents retrieved. Neutral documents are those that don't add to or detract from the relevance based on the retrieval criteria—they can be considered as neither helpful nor harmful to the evaluation of relevance.

When neutral documents are included in the validation process, they do not contribute to the count of relevant documents. Since they do not influence the relevant document count while also remaining independent of the retrieval count, they don't alter the Precision metric. Precision only changes when the numbers of relevant or irrelevant documents retrieved change distinctly.

Thus, the presence of neutral documents does not modify the ratio that defines Precision, affirming the idea that these documents do not impact the overall evaluation of how well the retrieval process is performing in terms of relevance to the user's query.