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Is CodeProject's Voting system really smart?

, 25 Apr 2004 CPOL 129.3K 19
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In this article I continue my discussion of the CodeProject''s voting system.

Introduction

This is a sequel of the article called "CodeProject's Article voting system" in which I have discussed two voting models, one of which I thought is used on the CodeProject's website.

As far as I was corrected by Chris Maunder who provided me with the model that is really used, I have decided to analyze this model too.

In this article you will find the rating counting algorithm, the description of its model and then some analysis of it.

Rating counting algorithm

The following description was cut and pasted from the following post "Excellent analysis. Unfortunately not quite correct":

Each article on CodeProject has associated with it a Vote Total (Vt), a Weight Total (Wt), and a number of votes (N). When a member votes, the system adds the weight of their vote (dependant on membership level) to Wt, and the rating itself multiplied by their weight to Vt. The rating of an article is then R = Vt / Wt.

If everyone has a weight of 1 then Wt = N, and R = Vt / N. Having differing weights, though, means that when a gold member (weight = 4) and bronze member (weight = 1) vote, the vote is weighted towards the gold:

Assume Gold votes 5 and Bronze votes 1:
Wt = 4 + 1 = 5
Vt = 4 x 5 + 1 x 1 = 21
R = 4.2

This is quite clear and looks very reasonable as each person has its weight in the system that depends on its status. But does it really works? An answer to this question along with the probability model will be given in the following sections.

Voting probability model

In the algorithm described above we deal with two types of random variables:

  • - the peoples' vote values
  • - the person's weight in the system

Note that:

  1. , , and are independent when and
  2. , have the same distribution
  3. , have the same distribution

Now we can represent the algorithm given above by the following formula:

In this formula index means that is the rating after the 'th vote. It is also obvious that is the weight of the person who put in the vote and thus voted with the value .

Let us now assume that we have the following mean values of our random variables:

,

It is well known from the probability theory that for two random variables and :

If they are independent then:

Now we are ready to calculate the following mean value :


(These calculations are trivial and self descriptive)

In other words and doesn't depend anyhow from weights of the persons who participated in the voting!

It is also interesting to note that if the rating formula would be the following:

then the mean value of the rating would be i.e. independent from vote values!

Conclusions

In this article I have calculated the mean value of the rating that measures the quality of any article on CodeProject's website.

It was discovered that although the weight of each person in the system is taken into account in case when the vote and the weight are independent, the mean value of rating random variable doesn't depend on the weight. Even more, the mean value is also the same as the mean value for the two other voting models described in my previous article "CodeProject's Article voting system".

Note that if the vote values depend on person's weights then the rating mean value is different and involves the weights distribution. Thus this approach may be considered to be more general than simple approaches that do not involve weights.

References

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

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About the Author

Dr. Ivan S Zapreev
Instructor / Trainer Fontys Hogescholen
Netherlands Netherlands
A software architect, designer, and a researcher in formal methods, algorithms and tools. Bachelor and Masters degrees (with honors) in Theoretical Mathematics. PhD in Theoretical Computer Science. Nine (9), DBLP recognized, international research publications (http://tiny.cc/umwaux). Five (5) Codeproject articles (http://tiny.cc/qlwaux). Fiveteen (15) years of work experience in research, design and development of Verification Algorithms, Scientific Software, Embedded Systems and Web applications. Young, energetic, pragmatic, smart, quality demanding, proactive, and eager to take responsibility. Working to the fullest, used to solving large-scale multi-disciplinary problems targeting long-run goals. Looking for a new challenge in a field of research and technical leadership.

Experience with development processes: Waterfall model; V-model (Rational Unified Process); Agile (SCRUM)

Specialties:
* Doing formal and applied research in the field of System and Software Verification
* Acquiring information, sharing knowledge, lecturing, mentoring, motivating and evaluating people.
* Creating object oriented architectures and developing large scale projects.

Experience with tools:
ASD suite, Rational Rose, Borland Together, Eclipse, Rational Soda for Word, Idea, JBuilder4/5/6/7, jdk1.3-1.6, Ant 1.x.x, Make, WebSphere, Tomcat 3.x, Weblogic, MySQL, Matlab 6.5 SP13, Clear Case, Clear Quest, Microsoft Visio.

Experience with programming languages:
Java (5 years), C (5 years), C++ (4 years), UML (4 years), CSS (2 years), HTML (2 years), Modula2 (2 years), Oberon (2 years), Microsoft .NET C# (1.5 year, ASP), SQL (1 year), OQL (1 year), XML (1 years), CSH (1 years), EL-76 (1 year), Visual Basic .NET (0.5 years), Pick Basic (0.5 years), OCL (0.5 years), JSP (1 year), Scala (0.3 years)

Knowledge and use of Version Control Systems:
SVN, CVS, GIT, Clearcase, SCCS

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Comments and Discussions

 
QuestionIt is time for the next chalange Pin
Jacek Gajek6-Jan-12 2:16
memberJacek Gajek6-Jan-12 2:16 
GeneralTrue in a perfect world Pin
Chris Maunder30-Apr-07 5:22
adminChris Maunder30-Apr-07 5:22 
GeneralRe: True in a perfect world Pin
Ivan S Zapreev7-Aug-07 2:05
memberIvan S Zapreev7-Aug-07 2:05 
GeneralRe: True in a perfect world Pin
Jacek Gajek6-Jan-12 2:07
memberJacek Gajek6-Jan-12 2:07 
GeneralOpen voting system! [modified] Pin
Mathieu Jacques16-Jan-07 7:43
memberMathieu Jacques16-Jan-07 7:43 
GeneralRe: Open voting system! Pin
Ivan S Zapreev7-Aug-07 2:02
memberIvan S Zapreev7-Aug-07 2:02 
GeneralMandatory message for each vote Pin
Mathieu Jacques16-Jan-07 7:35
memberMathieu Jacques16-Jan-07 7:35 
GeneralDifferent Distributions Pin
Sam NG20-Mar-06 19:06
memberSam NG20-Mar-06 19:06 
GeneralRe: Different Distributions Pin
Ivan S Zapreev21-Mar-06 5:49
memberIvan S Zapreev21-Mar-06 5:49 
GeneralI'd like to see the rating distribution Pin
reinux7-Sep-05 17:37
memberreinux7-Sep-05 17:37 
GeneralRe: I'd like to see the rating distribution Pin
Ivan S Zapreev7-Sep-05 22:25
memberIvan S Zapreev7-Sep-05 22:25 
GeneralRe: I'd like to see the rating distribution Pin
Mathieu Jacques16-Jan-07 7:22
memberMathieu Jacques16-Jan-07 7:22 
GeneralThe Yea/Nea/Meh Model Pin
Christopher Lord26-Apr-04 8:37
memberChristopher Lord26-Apr-04 8:37 
GeneralRookie/Guru Pin
Wackatronic26-Apr-04 8:06
memberWackatronic26-Apr-04 8:06 
GeneralRe: Rookie/Guru Pin
Jeff Varszegi26-Apr-04 8:25
memberJeff Varszegi26-Apr-04 8:25 
GeneralRe: Rookie/Guru Pin
Wackatronic26-Apr-04 9:01
memberWackatronic26-Apr-04 9:01 
GeneralRe: Rookie/Guru Pin
Jeff Varszegi26-Apr-04 9:27
memberJeff Varszegi26-Apr-04 9:27 
GeneralRe: Rookie/Guru Pin
Wackatronic26-Apr-04 9:34
memberWackatronic26-Apr-04 9:34 
GeneralRe: Rookie/Guru Pin
Jeff Varszegi26-Apr-04 9:40
memberJeff Varszegi26-Apr-04 9:40 
GeneralRe: Rookie/Guru Pin
Wackatronic26-Apr-04 11:46
memberWackatronic26-Apr-04 11:46 
Generalетить. What an article. Pin
gevorg26-Apr-04 7:25
membergevorg26-Apr-04 7:25 
GeneralRe: етить. What an article. Pin
Ivan S Zapreev26-Apr-04 22:47
memberIvan S Zapreev26-Apr-04 22:47 
QuestionWhat a waste of time... Pin
ToneEngel26-Apr-04 1:39
memberToneEngel26-Apr-04 1:39 
AnswerRe: What a waste of time... Pin
Ivan S Zapreev26-Apr-04 1:47
memberIvan S Zapreev26-Apr-04 1:47 
QuestionStatistics? Pin
Luca Piccarreta26-Apr-04 1:24
memberLuca Piccarreta26-Apr-04 1:24 

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