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+====== Troubleshooting Equality Scans ======
+Equals signs (%%=%%) are often used in scan clauses when you are looking for a specific symbol, country, exchange, etc. The equals sign can also be used to look for a specific numeric value in a scan clause, but you may not always get the results you expect. Let's look at an example:
+{{:scans:equalityscans01.png}}
+In the above chart, both the top MACD Line (12,26,9) and the bottom MACD Line (20,36,9) for HBI appear to have the same value: 0.800.
+===== Scanning for Equality =====
+Now let's run a scan to look for symbols where those two MACD Line values are equal to each other:
+<code>
+[type is stock] and [country is US] and [sma(20,volume) > 40000]
+and [close > 21]
+and [MACD Line(12,26,9) = MACD Line(20,36,9)]
+</code>
+If we ran this scan on the same date as the chart, the scan would net us only one result:
+{{:scans:equalityscans02.png}}
+Despite the fact that the HBI chart showed identical values for these two indicators, HBI does not appear in our scan results.
+The reason for this discrepancy is that the values displayed on the chart are rounded to a certain number of decimal points (typically 2 or 3) for display purposes. The values used by the Scan Engine are not rounded to this degree - the more precise values used by the Scan Engine are often not exactly equal. If the longer-term MACD Line (20,36,9) is 0.8003 and the shorter-term MACD Line (12,26,9) is 0.8004, the Scan Engine does not consider those two values to be equal.
+How can we fix our scan so we get the results we expect?
+===== Scanning for "Close Enough" =====
+When comparing one calculated value to another, it is better to replace the one "equals" clause with two "close enough" clauses, like this:
+<code>
+and [MACD Line(12,26,9) > [MACD Line(20,36,9) - 0.01]]
+and [MACD Line(12,26,9) <= [MACD Line(20,36,9) + 0.01]]
+</code>
+This tells the Scan Engine to return results where one MACD Line is within one cent above or below the other - not identical values, but extremely close to each other. When we run the updated scan, we see that HBI now appears in the scan results:
+{{:scans:equalityscans03.png}}
+For even greater precision, you could scan for values within one tenth of a cent of each other:
+<code>
+and [MACD Line(12,26,9) > [MACD Line(20,36,9) - 0.001]]
+and [MACD Line(12,26,9) <= [MACD Line(20,36,9) + 0.001]]
+</code>
+As long as the values are within that small range defined by the two clauses, they are "close enough" to be considered "equal" by our scan.
+===== Conclusion =====
+The equals sign is great for non-numeric comparisons, but should be used with caution when comparing numeric values. When you do need to compare numbers, it is better to use "close enough" clauses, defining a small range of values so similar that they are essentially equal.