Monday, November 28, 2011

Are these brokerages really any better or worse than each others?

 Globe and Mail ranked Canadian brokerages by the following table:


 RankBrokerCosts (/25)Trading (/25)Tools (/20)Account Info (20)Innovation (/10)Total (/100)
1Qtrade Investor16211518777
2Virtual Brokers23.518.51110871
3BMO InvestorLine1016.516.518.56.568
4Scotia iTrade1816.51313767.5
5RBC Direct Investing1017.51816566.5
6Credential Direct12.51614.518566
7TD Waterhouse101718114.560.5
8CIBC Investor's Edge14.513.5158657
9Disnat (Classic)10.511.515153.555.5
10Questrade1613.510.596.555.5
11National Bank Direct Brokerage8.510.51416.53.553
12HSBC InvestDirect1013610140



If the Globe and Mail scores are representative of the collective opinions of the traders and investors, are any of the brokerages any better or worse than the others?


In other words, are the scores really different? Let's put all scores in one column and the brokerage name in the other, and use Tukey's multiple comparison test to find out. Actually, let's use all 3 -- Bon Ferroni, Tukey and Scheffe.


Save the above table as z:\brokers.csv, and run the following SAS code. We found all 3 tests put all the brokerages into a single group. They are all the same by standards of Globe and Mail.



filename in 'z:\brokers.csv';
data mydata.brokers;
length broker $32;
infile in dsd dlm="," missover firstobs=2;
input Rank Broker $ Costs Trading Tools AcctInfo Innovation total;
run;


data mydata.brokers2(drop= Costs Trading Tools AcctInfo Innovation i);
set mydata.brokers(drop=rank total);
array attrs (*) _numeric_;
do i=1 to dim(attrs);
score=attrs(i);
output;
end;
run;


proc glm data=mydata.brokers2;
class broker;
model score = broker /solution e;
means broker /bon tukey scheffe alpha=0.05 ;
run;