  Objective: Our objective is to explore how public entities in the role of
platform providers can address this issue by enabling collaboration within
their OGD ecosystems, both in terms of the OGD published on the underpinning
platform, as well as any related Open Source Software (OSS) and standards.
Method: We conducted an exploratory multiple-case study of four OGD ecosystems
with diverse characteristics. Data was collected through semi-structured
interviews, and in one of the cases through a prolonged engagement. The data
was then coded using a set of \textit{apriori} codes. Results: The study
descriptively presents each case based on the coding, along with synthesis in
the form of a conceptual model that highlights different attributes of OGD
ecosystems. For example, we observe how collaboration can be enabled through
different types of ownership of the platform provider, how the ecosystem's
scope can vary, what roles the platform provider may undertake, how to enable
open collaboration, and how to collaborate in terms of data sharing, OSS
development, and standards. For each aspect, we provide recommendations based
on the explored cases that, together with the model, may help public entities
in designing and orchestrating new or existing OGD ecosystems. Conclusions: We
conclude that enabling and facilitating collaboration in an OGD ecosystem is a
complex exercise, yet believe that it offers new ways for public entities in
how they can leverage the power of open innovation to address their goals and
directives.
