Summary:
Significant investments in information systems (IS) over the past decades have led to
increasingly complex IS architectures in organisations, which are difficult to understand,
operate, and maintain. We investigate this development and associated challenges
through a conceptual model that distinguishes four constituent elements of IS architecture
complexity by differentiating technological from organisational aspects and
structural from dynamic aspects. Building on this conceptualisation, we hypothesise
relations between these four IS architecture complexity constructs and investigate
their impact on architectural outcomes (i.e., efficiency, flexibility, transparency, and
predictability). Using survey data from 249 IS managers, we test our model through
a partial least squares (PLS) approach to structural equation modelling (SEM). We find
that organisational complexity drives technological complexity and that structural complexity
drives dynamic complexity. We also demonstrate that increasing IS architecture
complexity has a significant negative impact on efficiency, flexibility, transparency, and
predictability. Finally, we show that enterprise architecture management (EAM) helps to
offset these negative effects by acting as a moderator in the relation between organisational
and technological IS architecture complexity. Thus, organisations without adequate
EAM are likely to face large increases in technological complexity due to
increasing organisational complexity, whereas organisations with adequate EAM exhibit
no such relation.