It is argued that case studies can be classified as either describing or ex
plaining a particular research phenomenon and as such researchers first nee
d to finalize which approach they are going to adopt. The concept of explan
ation suggests a realist approach and description suggests an interpretive
approach. Ii explanation is the target, the selection of a theoretical appr
oach for a longitudinal study is made more difficult as organizational cont
exts can alter radically from that in place at the initiation of a study-to
tally different approaches may be necessary to best explain the underlying
"reality" of the situation. This article suggests that Bhaskar's (1979, 198
6) philosophy of critical realism can provide some guidance as to the theor
etical approach to adopt. A framework is developed based on a critical real
ist argument for the consideration of both structure and agency in research
, the suggestion being that different organizational situations require dif
fering emphasis on structure or agency.