  Background: Establishing traceability from requirements documents to
downstream artifacts early can be beneficial as it allows engineers to reason
about requirements quality (e.g. completeness, consistency, redundancy).
However, creating such early traces is difficult if downstream artifacts do not
exist yet. Objective: We propose to use domain-specific taxonomies to establish
early traceability, raising the value and perceived benefits of trace links so
that they are also available at later development phases, e.g. in design,
testing or maintenance. Method: We developed a recommender system that suggests
trace links from requirements to a domain-specific taxonomy based on a series
of heuristics. We designed a controlled experiment to compare industry
practitioners' efficiency, accuracy, consistency and confidence with and
without support from the recommender. Results: We have piloted the experimental
material with seven practitioners. The analysis of self-reported confidence
suggests that the trace task itself is very challenging as both control and
treatment group report low confidence on correctness and completeness.
Conclusions: As a pilot, the experiment was successful since it provided
initial feedback on the performance of the recommender, insight on the
experimental material and illustrated that the collected data can be
meaningfully analysed.
