RDP 9307: Explaining Forward Discount Bias: Is it Anchoring? Equation (7′)

\begin{matrix} ({\bar{s}}_{t + 1} - {\bar{p}}_{t + 1}) = ρ ({\bar{s}}_{t} - {\bar{p}}_{t}) + e_{t + 1}, & 0 < ρ < 1 \end{matrix}