Gathering the Available Data

Having settled what indicators of happiness can be deemed acceptable, I continued by taking stock of the investigations that had actually used them. This was a laborious job. Some of the practical problems involved will be mentioned in section 5/1. As we will see 245 acceptable investigations were found. Some of their characteristics will be described in section 5/2. The listing of acceptable studies was only one step; the next was to make them accessible. This required that the data were formulated in the same language and that findings were summarized in a clear and comparable way. This procedure is reported in section 5/3. The abundant data having been organized conveniently, I got a better view on their limitations. In section 5/4 I will mention the most obvious ones and anticipate the problems of interpretation that arise in the next chapters.