# Vertical spacing inside \equation

I am writing my master's thesis and noticed that the spacing when using fractions is very small. T

$$\label{ASF} f_{ij}^{t}=\dfrac{\sum_{d=1}^{365}(Unique\; daily-user\; searches\; for\; i\; and\; j)_d}{\sum_{d=1}^{365}(Unique\; daily-user\; searches\; for\; i\; and\; any\; firm\; j \neq i)_d}$$


Can someone help? I am using the equation environment for to labeling.

I had to make the necessary changes to your code because it is has not been inserted. I have added only \displaystyle which makes the fraction more readable for a best increase linespacing.

It is very important to know a complete MWE and compilable code. At last I have used fittingly \text in math-mode as you can see, which provides better readability during reading.

\documentclass[a4paper,12pt]{article}
\usepackage{amssymb, mathtools}
\begin{document}
$$\label{ASF} f_{ij}^{t}=\frac{\displaystyle \sum_{d=1}^{365} (\text{Unique daily-user searches for } i \text{ and } j)_d}{\displaystyle \sum_{d=1}^{365}(\text{Unique daily-user searches for } i \text{ and any firm } j \neq i)_d}$$
\end{document}