public void TestTrendRequest_IsValid_True_If_Enough_Valid_Values()
{
var dataList = DataList();
// Add invalid data point after 5 more recent points
dataList.Add(new CoreDataSet
{
Value = ValueData.NullValue,
Denominator = 4,
Count = 8,
Year = 2000
});
var trendRequest = new TrendRequest()
{
UnitValue = 1,
ValueTypeId = ValueTypeIds.Proportion,
YearRange = 1,
Data = dataList
};
string validationMessage = null;
var isValid = trendRequest.IsValid(ref validationMessage);
Assert.IsTrue(isValid, validationMessage);
}
public void Write(TrendRequest trendRequest, TrendMarkerResult trendMarkerResult)
{
foreach (var data in trendRequest.Data)
{
_csvWriter.AddLine(data.AreaCode, data.Year, data.Value, data.Denominator, data.Count);
}
_csvWriter.AddLine("", "", "", "", "", trendMarkerResult.ChiSquare, trendMarkerResult.Slope, trendMarkerResult.Intercept,
trendMarkerResult.Marker, trendMarkerResult.NumberOfPointsUsedInCalculation, trendMarkerResult.Message);
}
public TrendMarkerResult GetTrendMarkerResult(IndicatorMetadata indicatorMetadata, Grouping grouping, IList<CoreDataSet> dataList)
{
var trendRequest = new TrendRequest
{
UnitValue = indicatorMetadata.Unit.Value,
ValueTypeId = indicatorMetadata.ValueTypeId,
Data = dataList,
YearRange = grouping.YearRange,
};
var result = _trendCalculator.GetResults(trendRequest);
return result;
}
public void TestTrendRequest_IsValid_True_If_Enough_Recent_Values()
{
var trendRequest = new TrendRequest()
{
UnitValue = 1,
ValueTypeId = ValueTypeIds.Proportion,
YearRange = 1,
Data = DataList()
};
string validationMessage = null;
var isValid = trendRequest.IsValid(ref validationMessage);
Assert.IsTrue(isValid, validationMessage);
}
public void TestTrendRequest_IsValid_False_If_Value_Invalid()
{
var dataList = DataList();
dataList[0].Value = ValueData.NullValue;
var trendRequest = new TrendRequest()
{
UnitValue = 1,
ValueTypeId = ValueTypeIds.Proportion,
YearRange = 1,
Data = dataList
};
string validationMessage = null;
trendRequest.IsValid(ref validationMessage);
Assert.AreEqual("Not enough data points with valid values to calculate recent trend", validationMessage);
}
public void TestTrendRequestIsInvalidForYearRangeGreaterThan1()
{
var trendRequest = new TrendRequest()
{
UnitValue = 1,
ValueTypeId = ValueTypeIds.Proportion,
YearRange = 3
};
string validationMessage = null;
trendRequest.IsValid(ref validationMessage);
Assert.IsTrue(validationMessage == "The recent trend cannot be calculated for this year range");
}
public void TestTrendRequestIsInvalidForNonRelevantValueType()
{
var trendRequest = new TrendRequest()
{
UnitValue = 1,
ValueTypeId = ValueTypeIds.Count,
YearRange = 1
};
string validationMessage = null;
trendRequest.IsValid(ref validationMessage);
Assert.IsTrue(validationMessage == "The recent trend cannot be calculated for this value type");
}
public TrendMarkerResult GetResults(TrendRequest trendRequest)
{
return CalculateTrend(trendRequest);
}
private bool IsSignificant(TrendRequest trendRequest, ref int pointsUsed, ref double chiSquare, ref string message)
{
chiSquare = 0.0;
if (trendRequest.IsValid(ref message) == false)
{
pointsUsed = 0;
return false;
}
// Chi squared confidence
const double chiSquared99Point8 = 9.54953570608324; // inExcel =CHIINV(0.002,1)
double chiSquaredConfidence = chiSquared99Point8;
var fullDataList = trendRequest.Data.ToList();
for (int pointsToUse = MinimumNumberOfPoints; pointsToUse <= fullDataList.Count; pointsToUse++)
{
pointsUsed = pointsToUse;
double sumOfr = 0;
double sumOfn = 0;
double sumOfrAndt = 0;
double sumOfnAndt = 0;
double sumOfnAndtSq = 0;
double t = pointsUsed;
var dataList = GetMostRecentDataOrderedByIncreasingYear(fullDataList, pointsToUse);
foreach (var coreDataSet in dataList)
{
var r = coreDataSet.Count.Value;
var n = coreDataSet.Denominator;
sumOfr += r;
sumOfn += n;
sumOfrAndt += r * t;
sumOfnAndt += n * t;
sumOfnAndtSq += n * (t * t);
t--;
}
var sumPart1 = ((sumOfn * sumOfrAndt) - (sumOfr * sumOfnAndt));
chiSquare = (sumOfn * (sumPart1 * sumPart1)) /
(sumOfr * (sumOfn - sumOfr) * (sumOfn * sumOfnAndtSq - (sumOfnAndt * sumOfnAndt)));
if (chiSquare > chiSquaredConfidence)
{
return true;
}
}
return false;
}
private TrendMarkerResult CalculateTrend(TrendRequest trendRequest, int pointsUsed = 0)
{
var message = string.Empty;
var chiSquare = 0.0;
// Is there a significant trend
var isSignificant = IsSignificant(trendRequest, ref pointsUsed, ref chiSquare, ref message);
// Trend line
TrendLine trendLine;
if (isSignificant)
{
var values = GetMostRecentDataOrderedByIncreasingYear(trendRequest.Data, pointsUsed)
.Select(x => x.Value)
.ToList();
trendLine = GetSlopeAndIntercept(values, trendRequest.ValueTypeId, trendRequest.UnitValue);
}
else
{
trendLine = new TrendLine();
}
// Trend marker
TrendMarker marker;
if (isSignificant)
{
marker = trendLine.SlopeBeta > 0 ? TrendMarker.Increasing : TrendMarker.Decreasing;
}
else
{
marker = pointsUsed > 0 ? TrendMarker.NoChange : TrendMarker.CannotBeCalculated;
}
// Return results
return new TrendMarkerResult()
{
Slope = trendLine.SlopeBeta,
Intercept = trendLine.InterceptAlpha,
NumberOfPointsUsedInCalculation = pointsUsed,
Marker = marker,
IsSignificant = isSignificant,
ChiSquare = chiSquare,
Message = message
};
}
