The three main economic factors that you would want to research as evidence of the economies strengths or weaknesses is as follows:
Inflation: - this tends to be a significant sign for security markets. It tends to determine how much of the investment is being lost. It also determines the rate of return amount you will need to compensate for this loss. - I advise you look up inflation.
GDP: The GDP is important to inflation. It tends to be an important economic component all on its own. - I advise you look up GDP for more information.
Labor Market Data: Focus point for economists which are the total employment and unemployment rates. - Again look up Labor Market Data for more information.
Hope this helps.