Which of the following is NOT a factor influencing aggregate demand?

In macroeconomics, aggregate demand refers to the total demand for goods and services in an economy at a given overall price level and in a given time period. Factors that influence aggregate demand include consumption, investment spending, government spending, and net exports.

Investment spending by businesses affects aggregate demand directly as it reflects the spending on capital goods that contribute to future production. Government spending also plays a significant role in influencing aggregate demand since it includes expenditure on public services, infrastructure, and other government projects that directly stimulate economic activity. Net exports, which represent the difference between a country's exports and imports, also influence aggregate demand since a surplus in net exports contributes positively while a deficit detracts from it.

In contrast, changes in labor productivity do not directly influence aggregate demand. While increased labor productivity can lead to higher output and, over time, may influence potential GDP and economic growth, it primarily affects the supply side of the economy. Labor productivity improvements mean that the economy can produce more goods with the same amount of labor, but it doesn't inherently change the aggregate demand within a specific timeframe. Therefore, it is categorized differently from the direct components that constitute aggregate demand, making it the correct answer to the question.