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Posts Tagged ‘prediction’

Predicting the stock market: it’s normally too late

With worries about Greek exit from the eurozone, with the unlikelihood of further quantitative easing in the USA and the UK, with interest rates likely to rise in the medium term, and with Chinese growth predicted to be more moderate, many market analysts are forecasting that stock markets are likely to fall in the near future. Indeed, markets are already down over the past few weeks. Since late April/early May, the FTSE is down 4.5%; the German DAX index is down 7.0%; the French CAC40 index is down 6.9%; and the US Dow Jones index is down 2.3%. But does this give us an indication of what is likely to happen over the coming months?

If stock markets were perfectly efficient, then all possible information about the future will already have been taken into account and will all be reflected in current share prices. It would be impossible to ‘get ahead of the game’.

It is only if market participants have imperfect information and if you have better information than other people that you can are likely to predict correctly what will happen. Even then, the markets might be buffeted by random and hence unpredictable shocks.

Some people correctly predicted things in the past: such as crashes or booms. But in many cases, this was luck and their subsequent predictions have proved to be wrong. When financial advisers or newspaper columnists give advice, they are often wrong. If they were reliably right, then people would follow their advice and markets would rapidly adjust to their predictions.

If Greece were definitely to exit the euro, if interest rates were definitely to rise in the near future, if it became generally believed that stock markets were overvalued, then stock markets would probably fall. But these things may not happen. After all, people have been predicting a rise in interest rates from their ultra-low levels for many months – and it hasn’t happened yet, and may not happen for some time to come – but it may!

If you want to buy shares, you might just as well buy them at random – or randomly sell any you already have. As Tetlock says, quoted in the Nasdaq article:

“Even the most astute observers will fail to outperform random prediction generators – the functional equivalent of dart-throwing chimps.”

And yet, people do believe that they can predict what is going to happen to stock markets – if not precisely, then at least roughly. Are they deluded, or can looking calmly at likely political and economic events put them one step ahead of other people who perhaps behave more reactively and emotionally?

Bond rout spells disaster for stock markets as global credit kraken awakens The Telegraph, John Ficenec (14/6/15)
Comment: Many imponderables for markets The Scotsman, Bill Jamieson (14/6/15)
How Ignoring Stock Market Forecasts Will make you a better investor Forbes, Ky Trang Ho (6/6/15)
The Predictions Racket Nasdaq, AdviceIQ, Jason Lina (21/5/15)

Questions

  1. Why may a return of rising interest rates lead to a ‘meltdown in equity prices’? Why might it not?
  2. Why have bond yields fallen dramatically since 2008?
  3. Why are bond yields rising again now and what significance might this have (or have had) for equity markets?
  4. Why may following the crowd often lead to buying high and selling low?
  5. Is there an asymmetry between buying and selling behaviour in stock markets?
  6. Will ignoring stock market forecasts make people better investors?
  7. “The stock market prices suggest that investors believe both the Federal Reserve and the Bank of England are bluffing about raising interest rates. That may be so, but it is an extremely risky game of chicken for investors to play.” Explain and discuss.
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Getting out the crystal ball

The New Year is a time for reflection and prediction. What will the New Year bring? What does the longer-term future hold? Here are two articles from The Guardian that look into the future.

The first, by Larry Elliott, considers a number of scenarios and policy options. Although not totally doom laden, the article is not exactly cheery in its predictions. Perhaps ‘life will go on’ and the global economy will muddle through. But perhaps a new recession is around the corner or, even worse, the world is at a tipping point when things are fundamentally changing. Unless policy-makers are careful, clever and co-ordinated, perhaps a new dark age may be looming. But who knows?

Which brings us to the second article, by Gaby Hinsliff. This argues that people are pretty hopeless at predicting. “History is littered with supposed dead certs that didn’t happen – Greece leaving the euro, the premature collapse of the coalition – and wholly unimagined events that came to pass.” And economists and financial experts are little better.

Two years ago, The Observer challenged a panel of City investors to pick a portfolio of stocks and rated their performance against that of Orlando, a ginger cat who selected his portfolio by tossing a toy mouse at a sheet of paper. Inevitably, the cat triumphed.

But is this fair? If capital markets are relatively efficient, stock prices today already reflect knowable information about the future, but clearly not unknowable information.

It’s the same with economies. When information is already to hand, such as a pre-announced tax change, then its effects, ceteris paribus, can be estimated – at least roughly.

But it’s the ‘ceteris paribus‘ assumption that’s the problem. Other things are not equal. The world is constantly changing and there are all sorts of unpredictable events that will influence the outcomes of economic policy and of economic decisions more generally. And central to the problem are people’s attitudes and confidence. Mood can swing quite dramatically, from irrational exuberance to deep pessimism. And such mood changes – often triggered by some exogenous factor, such as an international dispute, an election or unexpected economic news – can rapidly gather momentum and have significant effects.

Predicting the long-term future is both easier and more difficult: easier, in that short-term cyclical effects are less relevant; more difficult in that changes that have not yet happened, such as technological changes or changes in working practices, may themselves be key determinants of the future global economy.

One of the most salutary lessons is to look at predictions made in the past about the world today and at just how wrong they have proved to be. Perhaps we need to call on Orlando more frequently.

Why ‘life will go on’ thesis about global economy might not pass muster in 2015 The Guardian, Larry Elliott (28/12/14)
Who knows what the new year holds? Certainly none of us The Guardian, Gaby Hinsliff (26/12/14)

Questions

  1. Give some examples of factors that could have a major influence on the global economy, but which are unpredictable.
  2. Is economic forecasting still worthwhile? Explain.
  3. Look at some macroeconomic forecasts made in the past about the world today. You might want to look at forecasts of agencies such as the IMF, the OECD, the World Bank and the European Commission. You can find links in the Economics Network’s Economic Data freely available online. Explain why such forecasts have differed from the actual outcome.
  4. Why, if capital markets were perfect, might Orlando be just as good as a top investment manager at predicting the future course of share prices?
  5. In what ways is economic forecasting similar to and different from weather forecasting in its methods, its use of data and its reliability?
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