  The target trial is an increasingly popular conceptual device for guiding the
design and analysis of observational studies that seek to perform causal
inference. As tends to occur with concepts like this, there is variability in
how certain aspects of the approach are understood, which may lead to
potentially consequential differences in how the approach is taught,
implemented, and interpreted in practice. In this paper, we consider two of
these aspects: how the target trial should be specified, and relatedly, how the
target trial fits within a formal causal inference framework. We first describe
two challenges with what we call the "aligned" approach to target trial
specification, which is common in evaluations of medical interventions using
healthcare databases and seeks to specify a target trial that is closely
aligned to the observational data so that all protocol components apart from
randomization can be closely emulated. We then argue how these challenges can
be circumvented by an approach that focusses on specifying the "ideal" target
trial: a trial with certain idealized aspects that ensure it is relevant to
answer the research question. In essence, this approach is applicable in a
broader range of settings and enables systematic assessment of all potential
sources of causal bias. Importantly, this view provides clarification for how
the target trial approach fits within a formal causal inference framework.
