price level) have adjusted to equate money demand and money supply. The quantitative relation between velocity and money demand is given by Velocity = Nominal Transactions (however defined) divided by Nominal Money Demand. Indirect measurement In practice, attempts to measure the velocity of money are usually indirect. The transactions velocity can be computed as where is the velocity of money for all transactions in a given time frame; is the price level; is the aggregate real value of transactions in a given time frame; and is the total nominal amount of money in circulation on average in the economy (see “Money supply” for details). Thus is the total nominal amount of transactions per period. Values of and permit calculation of . Similarly, the income velocity of money may be written as where is the velocity for transactions counting towards national or domestic product; is an index of real expenditures (on newly produced goods and services); and is nominal national or domestic product. Determination The determinants and consequent stability of the velocity of money are a subject of controversy across and within schools of economic thought. Those favoring a quantity theory of money have tended to believe that, in the absence of inflationary or deflationary expectations, velocity will be technologically determined and stable, and that such expectations will not generally arise without a signal that overall prices have changed or will change. This determinant has come under scrutiny in 2020-2021 as the levels of M1 and M2 Money Supply grow at an increasingly volatile rate while Velocity of M1 and M2 flattens to stable new low of a 1.10 ratio. While interest rates have remained stable under the Fed Rate, the economy is saving more M1 and M2 rather than consuming, in the expectations that Fed benchmark interest rate increases from all-time lows of 0.50%. During this time, inflation has risen to new decade highs without the velocity of money. Criticism Ludwig von Mises in a 1968 letter to Henry Hazlitt said: "The main deficiency of the velocity of circulation concept is that it does not start from the actions of individuals but looks at the problem from the angle of the whole economic system. This concept in itself is a vicious mode of approaching the problem of prices and purchasing power. It is assumed that, other things being equal, prices must change in proportion to the changes occurring in the