Hi Shi Ern,
Here are my thoughts.
Firstly, if everyone just rely on P/E, P/B, EV/EBITDA to buy shares, all investors need is a stock screener, perform some quick filters and everyone will be rich.
Next, the financial ratios you used is part of value investing. It indicates how cheap a stock can be, but cheap doesn't equates to value and it certainly doesn't tell the entire picture. A stock can be cheap forever (value trap) for various reasons, but the most probable reason is the company is fundamentally inferior. To mitigate the problem of poor quality, famed investor Joel Greenblatt (who popularized the magic formula - EV/EBIT) paired EV/EBIT with ROIC and ranked them. ROIC gives an indication on how efficient (quality) the company is in generating returns per unit of invested capital. Joel Greenblatt backtested this from 1988-2009 and the results showed returns in excess of 20%+. You can read more in "The Little Book That Still Beats the Market by Joel Greenblatt" or just google it.
However, in current times, as almost every serious investor would know about this, this approach is not as valuable as before.
In addition, it is very important to understand the meaning behind the numbers. For instance, relying solely on P/B will skew yours results towards assets-heavy companies - financials, insurers, real estates etc. You will almost never be able to shortlist an asset-light company like Facebook, Ebay or UMS Holdings.
As mentioned by someone, the backtested period of 2 years is way too short. Try backtesting it during 2006-2008 and during 2009-2011, you will draw very different conclusions. This is similar to judging the capability of an investor, based on a short investing record.
Anyhow, I do believe that Quant does works, but one must know how to mitigate the pitfalls of different models. Renaissance Technologies is founded by James Simons, a mathematician, they do not hire people from finance backgrounds and 1/3 of their staff have PHDs. Their Medallion fund generated over 35% returns over a 20 years period (due to high leverage and highly diversified positions), which beats the legendary Buffett's record by a mile. Somehow, Renaissance Technologies is not well known to Main-Street.
In addition, as mentioned previously, your Quant model is way too simple. You may take reference to the OVS Stock Portfolio by Jae Jun from Old School Value. He do disclose his methodologies and is based on fundamental metrics and he has backtested it (I can't recall the returns). Do note that he recommends using it as a screener though. As mentioned earlier, as he commercialized his OVS Stock Portfolio, as more people uses it, the value "reverts to mean" or "loses value".
https://en.wikipedia.org/wiki/Renaissance_Technologies
Lastly, if you are really interested in value investing using Quant, and is willing to put in the initial hard work to gain a foundation in value investing; I would encourage you to start by reading "F Wall Street by Joe Ponzio" and "Financial Statements by Thomas Ittelson". After finishing read these, if it still doesn't bore you, then hop onto to Amazon and read the next 10 investment books recommended by Amazon's "Customers who bought this item also bought" data analytics tool. I did this, although I started with the classic - "The Intelligent Investor by Ben Graham".
Hope this helps.