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What is your opinion?

Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Please consider the following situation

Download Time Before Optimization : 10 Seconds
Download Time After Optimization : 5 Seconds

There are two 2 logic

First Logic:

((10-5) / 10) * 100 = 50

You can say after optimization we have reduced 50% download time.

Second Logic:

((10-5) / 5) * 100 = 100

If you compare Download Time After Optimization with the Download Time Before Optimization, you can say change is 100%.

I am with the seconds logic as it gives more optimized figure.

What is your opinion?

Is any calculation method wrong?


My blood is tested +ve for Java.
Alan Wanwierd
Ranch Hand

Joined: Jun 30, 2004
Posts: 624
There are 2 different things you are saying:

Firstly: After optimising the download is 50% faster
and secondly: Before optimising the download was 100% slower.

both statements are correct.

I'd be tempted to avoid confusion and say "performance much improved" !!
[ August 23, 2005: Message edited by: Adrian Wallace ]
Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Well we have already use flourishing language jargons to indicate performance gain�

My client is saying, �Dear I am not good at language, please use statistic to make me understood the performance gain�
Neeraj Dheer
Ranch Hand

Joined: Mar 30, 2005
Posts: 225
Your client refers to you as 'Dear' ???

That must be some client!!!
fred rosenberger
lowercase baba
Bartender

Joined: Oct 02, 2003
Posts: 11420
    
  16

You're saying that 5 is 1/2 of 10, and that 10 is twice 5. Same thing either way, it's just a question of how you want to spin it.

As i think Mark Twain said, "There are lies, damn lies, and statistics."


There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors
Ryan McGuire
Ranch Hand

Joined: Feb 18, 2005
Posts: 1011
    
    3
Originally posted by fred rosenberger:
You're saying that 5 is 1/2 of 10, and that 10 is twice 5. Same thing either way, it's just a question of how you want to spin it.

As i think Mark Twain said, "There are lies, damn lies, and statistics."


I disagree. When you talk about savings, it is generally understood that fractions/percentages are in terms of the original number. So cutting a 10 second time down to 5 seconds is a 50% improvement.

Let's say you cut the time down to 2 seconds. In terms of the original measurement, that's an 80% improvement. In terms of the new number, that would be a 400% improvement.


HOWEVER...
If you want the number to look better, you could use the rate of file transfer.

Files per minute before optimization: 6
Files per minute after optimization: 12

THAT would be 100% improvement. Just for comparison, let's say you got the transfer time for one file down to 2 seconds. That would be a rate of 30 files per minute. And that would be a speed improvement of 400%.

Some other tricks. If you're doing the optimization in phases, comparing the improvements made so far to the original number makes it look better.

So if your download time went from 10 sec to 5 sec to 2 sec. After the second round of optimizations, report that the speeds are now a 400% improvement over the original speed (instead of a 150% speed improvement over the first round of optimizations).

Another way to make the same measurement look good by measuring the "right" thing: Let's say that your new download software/hardware made the successful transfer percentage go from 99.85% to 99.95%. That's an improvement of only 0.10015%. Big deal. BUT if you measure failed transfers instead, you've made those go from 0.15% to 0.05%, which is an improvement of 67%. Which would you rather report: an improvement (increase) of of .1% in successful transfers or an improvement (reduction) of 67% in failed transfer failures?

I love statistics.
Mark Spritzler
ranger
Sheriff

Joined: Feb 05, 2001
Posts: 17257
    
    6

One says that you optimized it by speeding it up so that it only takes half the time.

The other says you optimized it and it used to take twice the time.

6 of one, half dozen of the other.

Mark


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