evaluation and ranking of market forecasters

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Background, motivation, and outcomes Methodology Results Conclusion Evaluation and Ranking of Market Forecasters Amir Salehipour ARC DECRA Fellow, University of Technology Sydney Joint work with David H. Bailey, Jonathan M. Borwein, and Marcos L´ opez de Prado September 29, 2017

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Page 1: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Evaluation and Ranking of Market Forecasters

Amir Salehipour

ARC DECRA Fellow, University of Technology Sydney

Joint work with David H. Bailey, Jonathan M. Borwein, andMarcos Lopez de Prado

September 29, 2017

Page 2: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Table of Contents

1 Background, motivation, and outcomes

2 MethodologyEvaluation algorithmTraining and testing the algorithm

3 ResultsForecaster accuracyTraders and investors

4 Conclusion

Page 3: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Background, motivation, and outcomes

Motivation

1 Many investors rely on market experts and forecasters when makinginvestment decisions.

2 Ranking and grading market forecasters provides investors with metrics onwhich they may choose forecasters with the best record of accuracy.

Aim of this studyThis study develops a novel ranking methodology to rank the market forecaster;in particular,

1 we distinguish forecasts by their time frame, and specificity, rather thanconsidering all forecasts equally important, and

2 we analyze the impact of the number of forecasts made by a particularforecaster.

Outcomes of this study

1 Across a dataset including 6,627 forecasts made by 68 forecasters, theaccuracy is around 48% implying the majority of forecasters perform atlevels not significantly different than chance.

Page 4: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Forecasts are not reliable enough!

“The forecasts were least useful when they mattered most” [Kaissar].

When analyzing a set of strategists’ predictions from 1999 to 2016, Kaissar foundthat forecasts were surprisingly unreliable during major inflection points [Kaissar]:

1 The strategists overestimated the S&P 500’s year-end price by 26.2% onaverage during the three recession years 2000 to 2002.

2 They underestimated the index’s level by 10.6% for the initial recovery year2003.

3 They overestimated the S&P 500’s year-end level by a whopping 64.3% in2008, but then underestimated the index by 10.9% for the first half of 2009.

Page 5: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Previous ranking

In 2012, the CXO Advisory Group ranked 68 forecasters based on their 6,582forecasts (forecasts made for the S&P 500 index) [CXO1].

That study acknowledged some weaknesses:

All predictions and forecasts were considered equally significant.

The analysis was not adjusted based on the number of forecasts made by aparticular forecaster: some experts made only a handful of predictions, whileothers made many; weighting these the same may lead to distortions whentheir forecasting records are compared.

Page 6: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Our ranking

We extended and advanced the previous ranking (therefore, we used the samedataset).

In particular, the major contributions of our study are:

Investigating in greater detail how market forecasters can be graded andranked;

developing an alternative and comprehensive ranking methodology;

recognizing and prioritizing forecasts by considering different weights forshort- and long-term forecasts, or for important/specific forecasts; and,

investigating and analyzing the most effective and meaningful metrics andmeasures.

Page 7: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Our ranking methodology

1 Part 1:

Every forecast statement is evaluated by calculating the return of the S&P500 index over four periods of one month, three months, nine months, and 12months.

The correctness of the forecast is determined in accordance with the timeframes.

2 Part 2

Each individual forecast is treated according to two factors of time frame andimportance/specificity (not all forecasts are equally important).

Long-term forecasts are treated as more significant than the short-termforecasts (because in the long-term underlying trends, if any, tend toovercome short-term noise; wt ∈ {0.25, 0.50, 0.75, 1.00}).

Specific forecasts are treated more important than non-specific ones(ws ∈ {0.50, 1.00}).

Page 8: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Forecaster’s score

Combined weight for a forecast:

w+i = wt × ws if forecast i is correct

w−i = wt × ws if forecast i is not correct

Where w+i implies when the forecast is true, and w−

i when it is false.

Then, score (accuracy) of a forecaster may be obtained as:

εj =Σ

nji=1w

+i

Σnji=1w

+i + Σ

nji=1w

−i

(1)

where j is the forecaster’s index, and nj is the total number of forecasts made byforecaster j .

Page 9: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Evaluation algorithm

We developed an algorithm, and coded that in the programming languagePython 2.7.

The algorithm reads every record in the dataset, processes the forecaststatements by assigning weights according to the six sets of pre-definedkeywords, and derives the forecasters score.

Keywords: Kt = {{Kt1}, {Kt2}, {Kt3}, {Kt4}}, and Ks = {{Ks1}, {Ks2}},where Kt includes subsets of keywords associated with time frames, and Ks

includes subsets of keywords associated with the importance of the forecasts.

The algorithm analyzes every forecast by applying both sets of keywords tofind any match, and then assigns weights accordingly.

Page 10: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Training and testing

Training the algorithm:

The performance of the algorithm depends on the keywords; we consider aset of 14 forecasters (about 20%) as the training dataset.

We manually analyze and evaluate every forecast in the training set, andcalculate the score of the forecasts.

Then we apply the algorithm to the training dataset, and compare theforecasters’ accuracy obtained by the algorithm against the one obtainedmanually. We update the sets of keywords accordingly.

After several attempts, we obtained an accuracy of 92.16% for thealgorithm’s performance.

Testing the algorithm:

We apply the algorithm to the remaining 54 forecasters, which we call thetesting dataset.

Page 11: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Forecasters accuracy

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Total accuracy versus accuracy per forecast and forecast share

Accuracy (This study) Accuracy per forecast Forecast share (no. of forecasts/total forecasts)

Because not every forecaster has made an equal number of forecasts, we analyzedthe accuracy per forecast:

ej =εjnj

(2)

Where, εj is obtained by the algorithm, and nj number of forecasts made byforecaster j .And forecast share of forecaster j :

sj =nj

Σjnj× 100 (3)

Page 12: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Forecasters accuracy vs CXO study

Accuracy gap grasps the changes in the forecasters accuracy between two studies:

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Gap = (Accuracy of this study - Accuracy of benchmark)

Positive values reflect improvement in the accuracy over the previous study, andnegative values reflect decreased accuracy.

In particular, 63.24% of forecasters have lower accuracy.

Page 13: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Forecasters time frame and specificity

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% of specific forecasts % of non-specific forecasts

Page 14: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Traders and investors

Long-term forecasters or “investors”, who have at least 30% of the forecasts withweights 0.75 and 1.00, and short-term forecasters or “traders”, with the majorityof the forecasts with weights 0.25 and 0.50.

We observed no forecaster has 50% or more of his forecasts with weights greaterthan 0.50.

Page 15: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Traders and investors

Investors

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Accuracy of forecasters in the investor group

Accuracy (This study) Percentage of forecasts with weights > 0.5

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Accuracy of forecasters in the trader group

Accuracy (This study) Percentage of forecasts with weights <= 0.5

Page 16: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Results – Summary

Major finding: the majority of forecasters perform at levels not significantlydifferent than chance, which makes it very difficult to tell if there is any skillpresent.

Across all forecasts, the accuracy is around 48%.

Two-thirds of forecasts predict as far as only a month.

Only one-third of forecasts predict periods over one month.

Two-thirds of forecasters have an accuracy level below 50%.

Only about 6% of forecasters have their accuracy values between 70%and 79%; the highest accuracy value is still below 80%.

Page 17: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Publication and awards

David H. Bailey, Jonathan M. Borwein, Amir Salehipour, and Marcos L opezde Prado. “Evaluation and ranking of market forecasters”. In: Journal ofInvestment Management. Forthcoming.

Awarded “Silver Bullet” award (20 May 2017).

Among the most viewed papers on the SSRN (www.ssrn.com) with a total2,762 views within six months (28 September 2017).

Page 18: Evaluation and Ranking of Market Forecasters

Background, motivation, and outcomes Methodology Results Conclusion

Bibliography

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Terry Burnham, “Why one economist isn’t running with the bulls: Dow 5,000 remains closer thanyou think”, PBS NewsHour, 21 May 2014, available at http://www.pbs.org/newshour/making-sense/one-economist-isnt-running-bulls-dow-5000-remains-closer-think/.

Nir Kaissar, “S&P 500 forecasts: Crystal ball or magic 8?,” Bloomberg News, 23 December 2016,available at https://www.bloomberg.com/gadfly/articles/2016-12-23/s-p-500-forecasts-mostly-hit-mark-until-they-matter-most.

Steve LeCompte, editor, “Guru grades”, CXO Advisory Group, 2013, available athttp://www.cxoadvisory.com/gurus/.

Steve LeCompte, editor, “The most intriguing gurus?”, CXO Advisory Group, 2009, available athttp://www.cxoadvisory.com/4025/investing-expertise/the-most-intriguing-gurus/.

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