As the complexity of investment strategies grows, so does the sophistication of tools needed to evaluate investment returns. One tool that provides a comprehensive understanding of investment returns is the Dividend-Adjusted Return. This metric reveals the total return of a stock, not merely relying on its capital appreciation, but also accounting for the dividends that shareholders receive over a specified holding period.

The Dividend-Adjusted Return calculation plays a crucial role in providing investors with a more precise evaluation of the return of income-generating security. It can be particularly valuable for those who engage in dividend investing – an investment strategy popular among risk-averse investors, who favor stocks with regular dividend payouts over those with high growth potential.

Calculating the Dividend-Adjusted Return involves an investor summing the total amount of dividends received to the price at which they sold the stock. This measure is a key component of total return, which considers all income streams of investment. By doing so, it presents a more holistic picture of an investment's performance.

However, it's essential to recognize that dividends can also impact a stock's share price. Following the ex-dividend date—the point at which a stock's price is adjusted to reflect the payout of a dividend—dividends are often perceived as a devaluation of a company. This occurrence might seem paradoxical at first, but it's a result of the company distributing a portion of its assets to shareholders, thereby reducing its total value.

Moreover, the Dividend-Adjusted Return is not exempt from the tax considerations that come into play with any investment strategy. Capital gains tax and dividend tax will need to be taken into account to arrive at the true profit of an investment. The interplay of these taxes can significantly influence an investor's net return, underscoring the need to factor these into any return calculations.

An important use case for Dividend-Adjusted Return is in determining the intrinsic value of a dividend-paying stock. This can be done using methods such as the Dividend Discount Model (DDM), which factors in a present-value calculation for expected future dividends. This method provides investors with a way to gauge whether a stock price is overvalued or undervalued in consideration of future dividends.

For the purpose of deriving accurate historical return data, it's also imperative to take dividends into account, assuming that all dividends were reinvested—a common practice among investors. This approach, endorsed by authorities like The Center for Research in Security Prices (CRSP) at the Booth School of Business at the University of Chicago, helps to factor in price changes resulting from stock splits and dividends.

The Dividend-Adjusted Return is a comprehensive tool that allows investors to evaluate the full return on their investments accurately. By factoring in dividends, capital appreciation, and relevant taxes, this metric provides a more holistic and realistic view of an investment's performance. Therefore, for those dealing with dividend-paying stocks, the Dividend-Adjusted Return is an essential part of their investment toolkit.

Summary:
An accurate historical return calculation for an investment should be done with the dividends in mind, such as assuming all dividends were reinvested, which is the most common way they are used.

Accurate historical information concerning prices and return should take the stock splits, dividends, and so-on into account. In a lesser-known context, dividend adjustment means a payment of accrued but yet-unpaid dividend amounts to the bearer of convertible preferred stock at the time that he or she converts them to shares of common stock.

So in that case it refers to an amount that is paid to a shareholder when they convert at a time that is not immediately after the preferred stock dividend was paid.

To confuse the issue further, when attempting to determine the intrinsic value of a dividend-paying stock, in consideration of the future dividends that are likely to be paid on it, there are methods such as the Dividend Discount Model (DDM) which factor in a present-value calculation for the expected future dividend. This helps investors determine whether a stock price is overvalued or undervalued.

The Center for Research in Security Prices (CRSP) at Booth School of Business at the University of Chicago has established standards for evaluating historical returns with respect to splits and dividends. Yahoo Finance offers an option to get Adjusted data which accounts for this.