Citation Chasing: Finding Studies Through Backward and Forward Searching

Database searches with carefully built strings are the backbone of most literature reviews, but they miss things. Inconsistent terminology, poor indexing, unusual titles and studies from neighbouring disciplines can all slip past even a well-designed search. Citation chasing, sometimes called snowballing, is one of the most effective ways to find what the databases miss. By following the references in key papers backwards and following later citations of those papers forwards, you can trace the network of research around a topic. This guide explains how to chase citations systematically, how to decide when to stop and how a source-linked assistant such as Yila can help you see why each paper cites the others.

What citation chasing is

Citation chasing comes in two main forms. Backward chasing means examining the reference lists of relevant papers to find earlier work they cite. Forward chasing means finding later papers that cite a relevant paper, usually with a citation index or a scholarly search engine.

Both work because researchers cite related work. A paper relevant to your question will probably cite, and be cited by, other relevant papers, whatever words they use in their titles and abstracts.

Why it matters

Citation chasing is particularly valuable when terminology is inconsistent, when a topic spans several disciplines, when relevant studies are published in journals that the main databases do not index well, and when the question is new enough that standard vocabulary has not settled.

Studies of systematic review methods have repeatedly found that citation chasing turns up relevant studies that database searches missed. For this reason many review guidelines recommend it as a supplementary search method.

Choose your seed papers

Citation chasing starts from a set of seed papers, which are studies you already know are relevant. Seed papers might come from your initial database search, from expert recommendations or from existing reviews. A good seed set covers the different facets of your question and includes both older foundational work and recent studies.

The quality of your seed set shapes your results. If every seed comes from the same research group or discipline, chasing may simply bring back more of the same. Deliberately include seeds from different traditions.

Backward chasing

For each seed paper, go through the reference list and identify references that look relevant. Titles alone can be misleading, so check the context in which each reference is cited. A reference cited in the introduction as background is different from one cited in the methods as the source of an instrument or in the discussion as a comparable study.

A source-linked assistant can speed this up. Asking Yila which studies a paper cites when comparing its findings, or which earlier work it builds its method on, returns answers linked to the relevant passages, so you can see why each reference was cited before you decide whether to follow it.

Record which seed each candidate came from. This helps you document your search and see which seeds were most productive.

Forward chasing

Forward chasing needs a citation index or a scholarly search engine that records which later papers cite a given paper. Different tools have different coverage, so results vary. Using more than one tool can improve completeness, though it also increases the number of duplicates to remove.

Highly cited seed papers can have hundreds or thousands of citing papers, many of which mention the seed only in passing. Screen citing papers by title and abstract first, using the same eligibility criteria as for your database search. Some tools let you search within the citing papers, which can narrow results to those that address your question directly.

Iterate thoughtfully

Snowballing can be repeated. Newly found relevant papers become seeds for another round of backward and forward chasing. Each round usually yields fewer new studies than the last. Decide in advance how many rounds you will do, or set a stopping rule, such as stopping when a round produces no new eligible studies.

Without a stopping rule, citation chasing can go on indefinitely. A clear rule makes the process manageable and reproducible.

Watch for citation bias

Citation chasing can reproduce the biases of the citation network. Studies with positive or striking results are often cited more than studies with null findings. Papers from prominent groups, high-profile journals and English-language sources may be overrepresented. Citation chasing alone can therefore produce a skewed sample of the literature.

This is one reason citation chasing should complement database searching rather than replace it. Combining methods reduces the risk that any single bias dominates.

Check how studies are cited

When a paper cites another, it does not always describe it accurately. Citation errors, such as misattributed findings, overstated conclusions or references to the wrong paper, are surprisingly common. If you rely on how a citing paper describes a study, you may inherit its errors.

Always go back to the original source before using a study in your review. Check what it actually found, not just what others say it found.

Document your process

Report citation chasing in your methods section. Describe the seed papers, the tools used for forward chasing, the number of rounds, the stopping rule and the number of studies identified through each method. Flow diagrams for systematic reviews usually include a separate box for records identified through other methods, which covers citation chasing.

Good documentation lets readers judge how complete your search was and lets others repeat it.

Manage the workload

Citation chasing can produce a lot of records, especially from forward searches on highly cited papers. Use reference management or screening software to remove duplicates and track decisions. Prioritise seeds that are central to your question, and consider limiting forward chasing for very highly cited papers to those citing papers that mention key concepts in their titles or abstracts.

Combine with other methods

Citation chasing works best alongside other supplementary methods, such as hand-searching key journals, contacting experts and searching grey literature. Together these methods catch studies that database searches miss for different reasons.

Citation chasing is a simple idea that rewards careful use. Choose diverse seeds, check why references were cited, set clear stopping rules, verify claims against original sources and document the process thoroughly, and it will substantially strengthen the completeness of your literature search.