Being just an ordinary investor, my common sense tells me that 'modified' approach to asset rotation method might work. I just finished reading Erickson's book on 'asset rotation' instead of MPT- asset allocation and pray. I assume that there are a plethora of variables that affect the market at any given period. I am thinking of going with traditional method (MPT) on my IRA holdings and use rotation method, not monthly but periodically on my taxable account. I would like to hear professional people's opinion. Thank you.