My main question refers to how minority interest (which only exists in consolidation method) impacts ratio analysis as compared to equity method or proportionaite consolidation
For example, how ROA, ROE, or is there any other ratio that is impacted by the minority interest as compared to the same ratio using the equity method, proportionate consolidation…
I guess in another way asked, what is minority interest considered in the BS? Is it considered equity, liability, or something in between? And how about in income statement, is it calculated before operating income?
Also, is consolidation method and acquisition method the same?
Thanks in advance
First, a big thumbs up for using the filed-under tags. 
Minority interest or non-controlling interest as it is often called, is usually listed in the equity section of the balace sheet which means that it will be included in all of the equity-based ratios.
On the income statement, minority interest is always included after operating income and usually is one of the last items listed on the income statement showing how much of the company’s earnings belong to its shareholders and how much belong to the other shareholders of the non-controlling interest.
Here is a filing with the SEC from a company with significant non-controlling interests as an example:
http://www.sec.gov/cgi-bin/viewer?action=view&cik=895930&accession_number=0000895930-12-000012&xbrl_type=v#