All the Guru Screens represents Stockopedia's interpretation of the guru/author's investment approach based on their published work(s) using our data-set. As a result, there are several reasons why our "Zulu" results may be different to, say, Company REFS:
Firstly, we use different data providers - REFS uses Hemscott (now bought by Morningstar) whereas we use Thomson Reuters. Differences in the standardisation of financial statements data and the compilation of consensus earnings estimates can lead to different results.
Secondly, REFS uses end of year data, whereas we use TTM (Trailing 12 month) data. This difference is very important. TTM data incorporates the latest quarterly or interim data as and when it comes available to give a more up to date view of a company's status. End of year data can be up to 15 months old by the time a company comes round to report again (12 months + 3 month reporting lag), leading to very stale ratio calculations as the company gets closer to its results date. Our philosophy is to give the most timely data possible. It should be noted though that in the case of the Zulu screen, Rolling rather than Trailing earnings are used in calculating forecast PEGs, PE ratios and EPS Growth forecasts which should minimise the difference.
Thirdly, minor proprietary difference in calculations or implementation of screen criteria can lead to slightly different results. We have tried to be as authentic as possible to the processes described in the books we've modelled and laboured over precision, but we can't guarantee they'll highlight the same stocks as other vendors. There are some optional/marginal criteria in Slater's books such as those relating to ROE and Cashflow that we've left out in order to deliver a broader portfolio of stocks.
Fourthly, REFS online publishes multiple lists titled "Lowest PEGs for growth stocks" etc, whereas our Zulu Principle page is the result of a more complete set of screening criteria. If you wish to just find the top ranked stocks by our version of Slater's PEG, you can find them here.
If you disagree with our approach to a given Guru's screening criteria (see the Rules tab on the screen for detail), please just raise a ticket via the Green Support Messenger and we'd be happy to discuss the detail. Please note: you can always duplicate the screen in order to add your own elements.