Does real estate underperform when compared to stocks and index funds?

My real estate assets yield 4-10% annually while stocks offer about 15%. What factors could explain this performance gap even with leveraged investments?

real estate can be a slower mover due to inherent costs like tranx fees & management hassles. stocks quickly ajust news and priceaction so yields can be higher. leverege helps but some overhead and illiqudity keeps r-e returns in check.