NEW YORK (ETF Expert) --There's a tendency in the financial media to wrap up calendar years with a focus on the "winners" and "losers." Inevitably, a large number of unsophisticated investors will allocate money to the so-called best performers, while avoiding any commitment to the underachievers.Herein lies one of the biggest mistakes that ETF enthusiasts make. Specifically, they view success through a prism of calendar-year data, ignoring genuine momentum found in relative strength or price ratios or even May-over-May performance. In fact, a calendar-year obsession has enormous potential to mislead. Keep in mind, it's not uncommon for worst performers in one year to reverse course entirely. In 2011, iShares MSCI Turkey ( TUR) lost a staggering -36.6%. In 2012? TUR was one of the best unleveraged ETF performers with an eye-popping 65.6% gain. Recognizing that 2012 "losers" may reverse course in 2013, I identified three ETF spaces that may do just that. Each of the asset areas discussed below under-performed broader large-cap equity benchmarks (i.e., S&P 500, MSCI All World) on a year-over-year basis. By the same token, each demonstrated greater relative strength than these benchmarks over the last five trading sessions. 1. Pipeline MLPs. Whether aggregating individual companies via exchange-traded fund or exchange-traded note, pipeline master limited partnerships offer something that few investment types can: about a 5% or better yield with about a 5% average company growth rate. Yet, 2012 was brutally unkind to the pipeline MLPs/energy sector due to falling demand, falling prices, regulatory fear/burden and fiscal cliff dividend tax uncertainty. As recently as Dec. 30, JP Morgan Alerian MLP ETN ( AMJ) was below a 200-day trendline. A few trading days later (Jan. 3), with the "cliff resolution" removing dividend tax uncertainty, things look very different.