Smart Software: About Those Methods?

July 23, 2019

An interesting paper germane to machine learning and smart software is available from Arxiv.org. The title? “Are We Really Making Much Progress? A Worrying Analysis of Recent Neural Recommendation Approaches”.

The punch line for this academic document is, in the view of DarkCyber:

No way.

Your view may be different, but you will have to read the document, check out the diagrams, and scan the supporting information available on Github at this link.

The main idea is:

In this work, we report the results of a systematic analysis of algorithmic proposals for top-n recommendation tasks. Specifically, we considered 18 algorithms that were presented at top-level research conferences in the last years. Only 7 of them could be reproduced with reasonable effort. For these methods, it however turned out that 6 of them can often be outperformed with comparably simple heuristic methods, e.g., based on nearest-neighbor or graph-based techniques. The remaining one clearly outperformed the baselines but did not consistently outperform a well-tuned non-neural linear ranking method. Overall, our work sheds light on a number of potential problems in today’s machine learning scholarship and calls for improved scientific practices in this area.

So back to my summary, “No way.”

Here’s a “oh, how interesting chart.” Note the spikes:

image

Several observations:

  1. In an effort to get something to work, those who think in terms of algorithms take shortcuts; that is, operate in a clever way to produce something that’s good enough. “Good enough” is pretty much a C grade or “passing.”
  2. Math whiz hand waving and MBA / lawyer ignorance of what human judgments operate within an algorithmic operation guarantee that “good enough” becomes “Let’s see if this makes money.” You can substitute “reduce costs” if you wish. No big difference.
  3. Users accept whatever outputs a smart system deliver. Most people believe that “computers are right.” There’s nothing DarkCyber can do to make people more aware.
  4. Algorithms can be fiddled in the following ways: [a] Let these numerical recipes and the idiosyncrasies of calculation will just do their thing; for example, drift off in a weird direction or produce the equivalent of white noise; [b] get skewed because of the data flowing into the system automagically (very risky) or via human subject matter experts (also very risky); [c] the programmers implementing the algorithm focus on the code, speed, and deadline, not how the outputs flow; for example, k-means can be really mean and Bayesian methods can bay at the moon.

Net net: Worth reading this analysis.

Stephen E Arnold, July 23, 2019

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