Comparability Principle of Accounting

Actually comparability is not any principle of accounting. It comes just from consistency principle of accounting. As per this, we have to use same policies in accounting, so that we can compare our financial statements. If every year, we will change the accounting policies, we can not compare the accounting statements.

For Example : 

1. We want to compare ABC's balance sheet of March 2013 with March 2012 for checking financial position has become strong or weak. It will only be possible if we have follow same policies. Without following same accounting policies, we can not compare two or more period balance sheet. 
2. We want to compare Y's Balance sheet with Z's balance sheet because both's business and industry is same. It will also be possible, if Y and Z will follow same IFRS and GAAP.