Simple answer is – they THINK differently and therefore PERCEIVE differently. THEN they have to be able to write their opinions down in words in a way that other similarly-trained experts will not disagree nor pick apart for being without foundation.
This EXAMPLE is from a list of Definitions on the Bank of Canada website Url below):
Housing affordability index
The housing affordability index is meant to measure the share of disposable income that a representative household would put toward housing-related expenses. The measure is a ratio of housing-related costs (mortgage payments and utility fees) to average household disposable income. The higher the ratio, the more difficult it is to afford a home.
Quarterly housing-related costs (denoted by c) are based on a series of monthly mortgage payments and utility fees that are calculated as follows:1
where r is the effective mortgage rate, which is a weighted average of discounted 1-, 3- and 5-year fixed-rate mortgages and the discounted variable-rate mortgage. The weights given to each interest rate are calculated from the Canadian Financial Monitor Survey provided by Ipsos Reid.2
N is the number of monthly payments (assumed to be 300 over 25 years) and M0 is the total value of the mortgage, where we assume a 95 per cent loan-to-value ratio, so that M0=(0.95)*P0.3 P0 is the 6-month moving average of the Multiple Listing Service average resale price; therefore, this measure strictly reflects existing homes and would include all housing types sold in Canada.
U refers to utility fees, which are based on the consumer price index for water, fuel and electricity.4 This series is scaled to the average level of spending on utilities by homeowners for their principal accommodation from the 2011 Survey of Household Spending.
The denominator, average household disposable income, is measured by using total quarterly household disposable income from the National Income and Expenditure Accounts, divided by the number of households in Canada. Our estimate of households is based on census data and is calculated using an extrapolative headship-rate method.5Footnotes
- 1. We do not include property taxes separately as an additional cost, since property taxes would already be removed from our measure of income to avoid double counting.[←]
- 2. Weights are assumed to be constant after the last data point.[←]
- 3. Our measure does not include mortgage insurance premiums.[←]
- 4. Before they are included in the index, these data are seasonally adjusted.[←]
- 5. For more details on this calculation, see United Nations Manual VII (1973) “Methods of Projecting Households and Families.”[←]
Here’s the site
Here’s the nifty interactive chart/graphs that got me TO that page
NB notice how the Affordability Index 1980 and 1990 are WORSE/HIGHER than today?