topic Re: Using standadized data for random forest and decision trees in SAS Data Science

Using standadized data for random forest and decision trees

geniusgenie — Thu, 25 May 2017 18:38:01 GMT

Hi,

I was wondering if anyone can help me?

Is this possible or right to use standardized data with random forest and decision trees?

If use with standardized data how algorithm treats that data?

Regards

Re: Using standadized data for random forest and decision trees

RadhikhaMyneni — Thu, 25 May 2017 20:00:40 GMT

Typically, you do not have to standardize data (z-score) with tree models (decision tree, random forest, gradient boosting etc.) as the algorithm tries to split at a place where classification/prediction is the best based on some criteria. Also, when you standardize, the interpretability gets little harder -- instead of saying age > 25 years is a good split, you have to say age > 1 std dev away from the mean is a good split etc. So for tree based models, I say, when you don't need it, why do the extra work.

Hope this helps,

Radhikha

Re: Using standadized data for random forest and decision trees

geniusgenie — Thu, 25 May 2017 22:53:47 GMT

Thanks for your reply Radhikha , but if we have already standardized it. Is it going to make any difference or going to produce wrong results?

Re: Using standadized data for random forest and decision trees

WendyCzika — Fri, 26 May 2017 00:41:58 GMT

Here is a really helpful article about standardizing that was just posted:

https://communities.sas.com/t5/SAS-Communities-Library/To-standardize-data-or-not-to-standardize-data-that-is-the/ta-p/361726

Re: Using standadized data for random forest and decision trees

geniusgenie — Fri, 26 May 2017 04:01:50 GMT

Hi Wendy,
Thanks for sharing this wonderful article which really clarifies things but my question remains same if my dataset is already standardized would it be wrong to use random forest and decision tree or its ok.

Plus, the dataset i have contains 5 colmuns which were difficult to be analysed without standardization for example all of them contain memory addresses like 0x00979876 etc. Only thing i did was to convert these 5 into decimal representation and standardized all of them.

Other columns have normal categorical values.

Hope this clarifies more.

Regards

Re: Using standadized data for random forest and decision trees

WendyCzika — Fri, 26 May 2017 13:44:36 GMT

I don't think it hurts that you have already standardized. With the tree-based algorithms, interval inputs are typically binned anyway (using bucket or equal-spaced binnin) before doing the split search, so it should be fine.

Re: Using standadized data for random forest and decision trees

ali1067 — Sat, 27 May 2017 05:06:16 GMT

Thanks a lot..