  The first inflationary model conceived was the one proposed by Starobinsky
which includes an additional term quadratic in the Ricci-scalar R in the
Einstein-Hilbert action. The model is now considered a target for several
future cosmic microwave background experiments given its compatibility with
current observational data. In this paper, we analyse the robustness of the
Starobinsky inflation by inserting it into a generalized scenario based on a
$\beta$-Starobinsky inflation potential, which is motivated through brane
inflation. In the Einstein frame, the generalized model recovers the original
model for $\beta=0$, whereas $\forall \beta \neq 0$ represents an extended
class of models that admit a wider range of solutions. We investigate limits on
$\beta$ from current cosmic microwave background and baryonic acoustic
oscillation data and find that only a small deviation from the original
scenario is allowed, $\beta=-0.08 \pm 0.12$ (68% C.L.), which is fully
compatible with zero and confirms the robustness of the Starobinsky
inflationary model in light of current observations.
