The ASX 200 is affected by a plethora of factors. The earnings reports of the stocks listed are one of the main driving factors of the index. Whether an earnings report is positive or negative can have a dramatic effect on the price of a stock, and hence the index.Changes to specific industry sectors can also have significant implications on the value of the ASX 200. For instance, when oil prices are low, oil-related sectors like mining, production and construction are suffering, leading to losses in the companies-constituents of the index.In addition, political and economic shifts that occur in Australia may also affect the index.