When merging query results from various information sources or from different search engines, popular methods based on available documents scores or on order ranks in returned lists can ensure fast response, but results are often inconsistent. Another approach is downloading contents of top documents for reindexing and reranking to create final ranked result list. This method guarantees better quality but is resource-consuming. In this paper, the authors compare two methods of merging search results: a) applying formulas to re-evaluate document based on different comhinations of returned order ranks, documents titles and snippets
b) Top-Down Reranking algorithm (TDR) gradually downloads, calculates scores and adds top documents from each source into the final list. The authors propose also sequentially ranking method by downloading best documents to create the final list of ranked results.