Following the ups-and-downs of the housing market can be difficult for the average home buyer or seller. Because of this, many Americans get in the market without a basic understanding of the forces currently driving home prices, mortgage rates, demand, etc. However, it can be beneficial to have a big-picture understanding of where things are and where they're headed before you make a move. These days, if you want a better grasp of what's happening in real estate, you have to start with inventory. So far this year, a lower than normal number of homes for sale has been the primary factor influencing home prices and overall sales. Take the most recent outlook from Fannie Mae's Economic & Strategic Research Group, for example. According to their forecast, inventory remains the big story, as it has been for the past year. “The narrative for the housing market hasn't changed over the past year,” Doug Duncan, Fannie Mae's chief economist, says. “A labor shortage continues to restrain homebuilding, and tight inventory is constraining sales and boosting home prices.” Despite those challenges, Duncan says the group expects mortgage rates will stay low enough to support buyers and home sales should rise 3.2 percent this year.