# Is it possible to tell anything about market structure if I have annual price data of the industries?

I have three goods:

• beer
• carp (fish)
• museum ticket

Is it possible to tell anything about market structure if I have annual price data of the industries? Here's the time-series plot on a single graph: I would like to give advice whether a firm should entry the market or not. Is is it possible to decode price data like "the incumbent firms must have been playing a Bertrand's price competition game at the carp market"? Or do I need further details to say anything about the market structure?

Is it possible to apply IO theory if I have only price data of an industry? I really need some clues, please.

That that we have linear supply and demand functions, pretty much the simplest case such that quantity supplied of good $i$ is: $$Q_{s,i,t} = \alpha_{0,i,t} + \alpha_{1,i,t} \cdot P_{i,t}$$ and quantity demanded is: $$Q_{d,i,t} = \beta_{0,i,t} + \beta_{1,i,t} \cdot P_{i,t}$$
In equilibrium $Q_{i,t}=Q_{d,i,t}=Q_{s,i,t}$ so substitute and solve: $$Q_{i,t} = \alpha_{0,i,t} + \alpha_{1,i,t} \cdot P_{i,t} = \beta_{0,i,t} + \beta_{1,i,t} \cdot P_{i,t}$$ $$P_{i,t} = \frac{\alpha_{0,i,t}-\beta_{0,i,t}}{\beta_{1,i,t} - \alpha_{1,i,t}}$$