General instructions

Run the tester over the specified range of years. Available data runs from 2003 through 2023 for most screens. You may start at any month of the year, but other than January can only run through 2022/2023.

Stocks are picked from the screens every holding period (between 1 and 120 months) and held for that period.

If you want to simulate actual trading, you can enter more parameters in the trading simulator.

You may give your backtest a name for convenience. If you use this backtest code in other testers, its name will be shown instead of a full description.

Dozens Backtest instructions

Select to screen to pick from. As with other testers, all stocks are held for the holding period, but there is also a trading period shorter than the holding period, which specifies how often new stocks are selected. The portfolio is split into enough partitions so stocks can be selected every trade date and held through other trade dates, until the holding period for those stocks is completed.

There are two ways to select the stocks to hold. First, you can simply specify the ranks in the screen. Or you can select the top-ranked stock(s) not already held in a different part of the portfolio. If all available selections are already held, the highest-ranking stock will be re-selected.

For a typical "dozens" strategy, the top one stock not held is selected every month, and held for one year. For a "dual semi" strategy, selected ranks from the screen are selected every quarter and held for 6 months.

If the trading simulator is being used, the rebalancing of the Dozens portfolio may be specified. This is independent of any rebalancing done within the separate start months. Rebalancing between the different parts of Dozens is more complicated than regular screen rebalancing, as it the entire portfolio can't be rebalanced at the same time. The tester offers three different methods of rebalancing. The first and simplest is to never rebalance.

The second method is to keep a virtual margin account apart from the portfolio. This is the default if run without the trading simulator. Every cycle of the tester, money is moved to or from this account to keep the current partition of the portfolio in proportion with the total (including the virtual margin account itself). This virtual accounting doesn't change the actual balance of the screen, but the stocks are all rebalanced to have the proportion as if the money were taken out.

The third rebalancing method is like the second, except a virtual cash account is used instead of a margin account. The only difference is the balance of this account can never go below zero. A variation of the cash method is to show the cash balance along with the rest of the screen, and account for it in the CAGR. This will make for slightly reduced, but more realistic, returns.