  Requirements engineering (RE) literature acknowledges the importance of early
stakeholder identification. The sources of requirements are many and also
constantly changing as the market and business constantly change.
  Identifying and consulting all stakeholders on the market is impractical;
thus many companies utilize indirect data sources, e.g. documents and
representatives of larger groups of stakeholders. However, companies often
collect irrelevant data or develop their products based on the sub-optimal
information sources that may lead to missing market opportunities.
  We propose a collaborative method for identification and selection of data
sources. The method consists of four steps and aims to build consensus between
different perspectives in an organization. We demonstrate the use of the method
with three industrial case studies. We have presented and statically validated
the method to support prioritization of stakeholders for MDRE. Our results show
that the method can support the identification and selection of data sources in
three ways: (1) by providing systematic steps to identify and prioritize data
sources for RE, (2) by highlighting and resolving discrepancies between
different perspectives in an organization, and (3) by analyzing the underlying
rationale for using certain data sources.
