Jim Cramer believes that the key to investing is being able to hold a stock for the long term.

"That is why diversification is so important, as this market occasionally goes off the deep end," the "Mad Money" host said.

Diversification can provide the most gain for the least amount of pain, he added.

So with this in mind, Cramer decided to help investors protect their portfolios with a diversification analysis. Investors provided their five top stocks, and he weighed in on whether they pass or fail the test of diversification.

The first portfolio he reviewed held Chevron, Apple, Schlumberger, Alphabet and Celgene. Unfortunately, this did not pass the test. He considered both Alphabet and Apple to be tech stocks and both Chevron and Schlumberger to be related to the oil patch.

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Cramer recommended keeping Chevron, Celgene and Apple. In a rare instance, he also allowed Alphabet to coexist in the portfolio, because it is such a high-quality stock to have, especially in the technology and hardware group.

As for Schlumberger, as much as he likes it, he swapped it out for industrial Dow Chemical for its 3.5 percent yield.

The next portfolio consisted of Apple, Starbucks, Boeing, Disney and Facebook.

"Oh no, Apple and Facebook? What we are going to have to do here is trade out of one of these. I hate to do this because my charitable trust owns both," Cramer said.

To further diversify, Cramer recommended adding Bristol-Myers to the portfolio.

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