The previous section may seem like rather a long list of things that you need to do before you even get started. Understanding the structure of the data and all the design issues are essential as they will help guard against erroneous conclusions and will be very valuable when it comes to interpretation of the results. The consequence of ignoring these issues may not seem evident for post-graduate analysis but are of important for analyses put out by international organisation or governments where they are creating a league table of results. The lessons from the results of the International Adult Literacy Survey in the mid nineties are a good example.