While the refrain from the Jimmy Buffett classic had nothing to do with investing, I continually remembered it while formulating this article because for many investors, 2019 will bring changes in latitudes and changes in attitudes. Buffett also sang ‘Nothing remains quite the same …’ and that also describes the volatility that we face this year.Some investors may want to change the structure of their portfolios. The tumult in the stock market that began last Fall and continues at time of writing has produced several kinds of fallout, among them a greater interest in value stocks.However, the change does not work quite as broadly as after previous corrections, according to Jay Nash, Senior Vice-President, Portfolio Manager and Investment Advisor at the London branch of National Bank and a 21-year veteran of the financial sector. This time around, the shell-shocked investor does not have as many places to turn. Dividend growth stocks took a lot of the hardest hits recently, a fact that will scare many investors away, ironic since they historically turn to dividend stocks after a market shock.Then too, some investors may consider the same change that many faced during the 2008 financial crisis. After the crash of that year, some investors who felt that they had a high risk tolerance when the market was buoyant had to re-evaluate their risk profiles when the crisis hit.Still, while some investors will understandably want to change the proportion of value stocks in their portfolios and shift some of their resources into that category, Nash advises against removing growth stocks completely.Nash says that data from 1999 underlines the point. At the time, a massive gap in performance occurred and those who switched to growth at the end of the year to chase numbers got crushed in the tech correction, he says.Nash points out that for those looking for dividends, companies with strong balance sheets and cash flow will likely still offer the best risk/return. In effect, that principle will never change.Dealing with the changes also means grappling with two broad and conflicting arguments. In the easier argument, one can make the case that the shock and hangover from the tumult would favor value stocks this year since these stocks generally perform better than some other stocks during times of reduced growth.In the more complex argument, one can make the case that the incredible drops in growth stocks created buying opportunities in that category. As longtime readers in this corner know, I consider the words ‘buying opportunity’ one of the most abused phrases in the entire lexicon of investing. Still, the selloff undeniably did create opportunities.Discerning the difference between a genuine opportunity created by a share price drop and a boondoggle that may not recover within the foreseeable future requires a bit of homework. While we do not have an airtight way of telling the difference, history can provide a decent guide, Nash says. If a stock has dipped well below its historical trading level relative to its earnings, it may indeed qualify as a genuine opportunity. With good earnings reports, the stock could come back to its ‘normal’ price level over time. Some major Canadian bank stocks listed on both Canadian and American exchanges fall into this category.Some of the changes can confuse investment choices. The tumult has meant that we do not face any shortage of opportunity, since the majority of sectors have dropped, Nash explains. In an easily recognizable example, the energy sector took some hard hits. The drop in West Texas Intermediate (WTI) oil pricing, and overall market fear, contributed to driving down the sector. Transportation issues and a massive price discount impacted those producing in Alberta more than many others, although the impact did not stop at Alberta’s borders.Related: 8 Questions in Assessing Your Exposure to Volatility in 2019 Related: The Financial Advisor as Emotional Guide At the end of 2018, the price of oil had fallen below what it costs some producers to get it out of the ground, so investing in these stocks requires a belief that the price of oil will eventually go higher, Nash explains.Meanwhile, Saudi Arabia, the world’s largest oil supplier wants the price to rise and Alberta aims for an 8.75% production cut. With those factors in mind, the odds of a price recovery look higher. While many companies’ stock prices remain at extremely depressed levels, large cap oil companies with good cash flows will benefit if the price of oil increases. Even if the price does not increase, these companies will be in a position to acquire assets, Nash explains. In that category, Nash’s picks include Suncor (TSX:SU NYSE:SU); Imperial Oil (TSX: IMO NYSE: IMO); and BP PLC (NYSE: BP).Another structural change may start soon. If we have in fact, hit the bottom, it appears likely that investors will invest large amounts in index funds, which will in turn lead to price increases in the underlying equities in these funds. Generally, those equities would qualify as buying opportunities.And while Jimmy Buffett certainly had it right when he said ‘Changes in latitudes, Changes in attitudes’ some principles of investing remain the same this year and in fact have become more important than ever. These include the need for expert advice from an accredited financial advisor or -- in the absence of an advisor -- the need for the do-it-yourself investor to undertake huge amounts of research homework before each trade. Disclosure: I do not hold any shares in any of the companies mentioned in this article and have no plans to purchase any of them.