Follow this step by step guide to draw a Split-Middle Line of Progress through a series of data points. Find the Mid-Date, the Mid-Rate, then the Quarter-Intersect Line and lastly adjust it up or down to get the Split-Middle Line of Progress
First you will divide the data points into 2 halves. If you have an even number of data points draw a vertical line between the two points. If you have an odd number of points draw the vertical line through the middle point
Once you have divided the data points in half you will get the mid-date by dividing each section in half again
After you have the mid-date you will get the mid-rate. Sometimes finding the mid-rate can be really confusing. The mid-rate is the middle score when the data points are ordered from least to greatest. If you are having trouble doing this visually create an x and y axis and put numbers on your graph to make it easier. Order the scores from least to greatest to find the middle score. You can do this visually or by actually ordering the scores.
To get the Quarter Intersect line of progress connect the intersection of the Mid-Date and Mid-Rate for each half to each other. To find the Split-Middle line of progress move the line so that there are an equal number of points on either side. In this particula example the line does not actually move very much. Any point that falls on the line is counted for both sides.