Use a transition matrix to predict the next step
A weekly survey records how each subscriber uses a publication
The matrix state order is read and skimmed. Columns represent the current state and rows represent the state next week. An entry is the proportion currently in its column state that will be in its row state next week
\[T = \begin{bmatrix} 0.6 & 0.3 \\ 0.4 & 0.7 \end{bmatrix}\]
The current-state column uses the same state order. Its entries are counts of subscribers
\[S_{\mathrm{now}} = \begin{bmatrix} 90 \\ 150 \end{bmatrix}\]