The European Union and the United States are currently negotiating the Transatlantic Trade and Investment Partnership also known as TTIP. The TTIP is a free trade agreement with the objective to encourage trade and economic growth. A transatlantic agreement between the EU and the US is believed to have a high potential to produce economic growth impulses and employment effects. Most trade tariffs between the US and the EU are relatively low. Removing the remaining trade tariffs will only have limited effects on the EU and US economies and the trade flows between these two regions. Therefore, the current TTIP negotiations focus on reducing the non-tariff barriers or NTB. NTB include quotas, levies, embargoes, sanctions and other indirect restrictions to trade, which are not tariffs. The EC estimates the potential economic stimulus of the free trade agreement at 90 billion euros for the US economy, 120 billion euros for the EU economy and 100 billion euros for the rest of the world. This master thesis shall discuss how the economic effects of a free trade area, like the TTIP, can be assessed. Furthermore, the thesis shall critically analyse one of the most comprehensive studies on the projected economic benefits of the TTIP agreement. The study “Reducing Transatlantic Barriers to Trade and Investment: An Economic Assessment” of the Centre for Economic Policy Research will be presented and analysed. The studys methodology, its economic model, the models underlying assumptions and the results will be explained and examined. The objective is to assess the applied methodology and the results.