tax avoidance data for dissertation

I will need to collect evidence on the Effective tax rate of around 50 firms. The data I will collect will be secondary data. It will be more meaningful to collect data on the cash effective tax rate to cater for timing differences and provisions made for financial reporting purposes which can be reverse in subsequent years. I will also need to collect and document information on the level of corporate governance of such organisations. Such information will be more qualitative and will need to be collected either from additional disclosures in the financial statements and/or from publications in the press. I will create a chart with numbers and data and will examine the relationship between the numbers and find their correlation and then plot a graph to see the relationship of their correlation. Quantitative analysis will be used to calculate mean, median, standard deviation of firms.