The corporate statutory tax rate is the tax rate set by the government that applies to the taxable income of corporations. This rate can vary significantly across countries and is subject to change over time. It is typically expressed as a percentage of the corporation's taxable income.

The effective tax rate is the ratio of total income tax expense to the pre-tax income or profits of a company. It represents the average rate at which a company's profits are taxed. The ETR takes into account all taxes paid or accrued during a specific period and is expressed as a percentage. It is a measure of the company's overall tax burden.

The formula for calculating the effective tax rate is: ETR = Income Tax Expense / Pre-tax Income

The ETR provides insights into a company's tax efficiency and can vary from year to year based on factors such as changes in tax laws, tax planning strategies, and the composition of a company's income.

The cash tax rate refers to the actual amount of cash a company pays in taxes during a specific period. It represents the cash outflow related to income taxes and takes into account any tax payments made to tax authorities. The cash tax rate considers the timing of tax payments and can differ from the accounting-based tax expense recognized on the income statement.

The cash tax rate is an important metric for analyzing a company's cash flow and liquidity. It helps assess the actual tax burden faced by a company and can be different from the effective tax rate due to factors like timing differences, tax credits, and tax deferrals.

It's worth noting that the effective tax rate and cash tax rate may not always be the same. Differences between the two can arise due to temporary or permanent differences between accounting income and taxable income, tax incentives, credits, and changes in tax laws.