Every earnings season the financial media fills headlines with whether or not companies met or missed Wall Street's latest quarterly expectations as if they mean anything. In fact long-term investors know that how a company does over three months is largely irrelevant, especially when it comes to midstream MLPs such as MPLX (NYSE: MPLX).

Yes, MPLX failed to live up to analyst estimates for sales and earnings this quarter. In fact it Q3 sales and EPS figures fell 6%, and 28% short of Wall Street's respective projections for the last three months.

Let's face it, when it comes to MLPs investors mainly care about the distribution profile. How high is the yield? How safe is the payout? What are its realistic long-term growth prospects? When it comes to capital intensive businesses such as MLPs, earnings are the wrong metric to look at.

That's because non-cash charges and large tax benefits derived from how this class of equity are structured means that earnings don't actually fund the quarterly distribution. This means that Wall Street's obsession with short-term earnings has very little to do with what long-term dividend investors really care about. 

So let's take a look at MPLX's latest earnings from the proper perspective. Specifically let's look at the three things that can and will effect MPLX's distribution profile and thus determine its long-term total returns. 

Results were actually fantastic

Metric Q3 2015 Q3 2014 Year over Year Change
Revenue  $148.6 million $138 million   +7.7%
Adjusted EBITDA  $64.6 million  $40.2 million  +61%
Distributable Cash Flow (DCF)  $52.5 million  $32.9 million  +60%
Quarterly Distribution  $0.47  $0.3575  +32%
Distribution Coverage Ratio (DCR)  1.13  1.18  -4.2%

Source: MPLX earnings release

As you can see from the table MPLX delivered where it counts, and in a big way. DCF is especially important to look at because that is what funds the quarterly distribution. In addition the fact that the DCR remains above 1.1 means that not only is the current 5.2% yield on solid footing, but it's capable of continued growth in the quarters ahead. MPLX is proud of its 11 consecutive quarters of strong distribution increases and has big plans to keep that streak alive. 

Growth prospects remain unchanged
In its earnings release MPLX's Chairman and CEO Gary Heminger told investors "We are enthusiastic about MPLX's future." He also reiterated the MLP's previous distribution growth guidance of 25% through 2017. 

Backing up those kinds of bold claims are MPLX's future drop down opportunities from its sponsor, general partner, and manager Marathon Petroleum Corp (NYSE: MPC). Marathon Petroleum is one of America's largest independent refiners and thus owns a substantial amount of midstream infrastructure. In fact, once Marathon has completed selling all of its qualifying midstream assets to MPLX the MLP's annual EBITDA is expected to increase $1.6 billion.

In order to keep MPLX's growth rate humming along, management expects Marathon Petroleum to provide substantial drop down support, possibly as early as 2016. However large asset drop downs from its sponsor are just part of MPLX's overall long-term growth plan.

MarkWest Merger is a major growth catalyst
MPLX expects its merger with MarkWest Energy Partners (NYSE: MWE) to be completed by the end of the year. That's important because of the massive amount of organic growth projects MarkWest is pursing in the Marcellus and Utica shale. For example, upon completion of the merger MPLX's growth capital spending will increase almost nine fold.

What's more MarkWest recently announced a $1 billion growth initiative that would add 2 billion cubic feet per day of natural gas gathering capacity in the Utica shale. 

That project represents just one part of the $6 billion to $9 billion in total growth projects MarkWest has planned for these two enormous gas formations. When combined with Marathon Petroleum's large access to cheaper capital this merger truly has the potential to fuel many years of strong distribution growth. In my opinion, such growth could extend far beyond management's current payout growth projections of 2019. 

Risks to watch for
Of course those kinds of optimistic growth plans need to be considered in the context of the current energy crash. Should oil and gas prices remain low for several years than it's possible that demand for these new projects could dry up. Similarly, credit markets may sour on energy investment which could starve MPLX's grand growth vision of the capital it needs to become reality. That in turn could cause it to fail to deliver on its existing growth projections. 

Bottom line: MPLX continues to fire on all cylinders so ignore the "earnings miss"
Wall Street's ongoing obsession with quarterly earnings should have no effect on long-term investors' thinking. Instead focus on MPLX's strong execution of its existing business strategy, and the impressive distribution growth it continues to deliver quarter after quarter.

Finally don't forget that thanks to its strong sponsor, upcoming merger with MarkWest, and its long-term fee-based contracts, MPLX's current cash flow growth is largely immune from energy prices; at least for the next few years. 

Adam Galas has no position in any stocks mentioned, however, he does lead The Grand Adventure dividend project, which recommends MPLX. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.