Components of Change is an analysis of household population change over the past twelve months from the current estimate. This analysis shows changes in population that are attributable to births, deaths, and net migration. This analysis does not include group quarter population changes.

The three elements of the Components of Change are based upon the prior 12 months from the most recent update. They are reported as whole numbers.

Categories include:

• Births (past 12 mths)

• Deaths (past 12 mths)

• Migration (past 12 mths)

These three factors determine net changes in population. Births add to the population, and deaths subtract from it. Net migration is added to the result. Net migration is in-migration (people moving into an area) minus out-migration (people moving out of an area). In some cases, net migration can be negative because more people moved out than new people moved in.

Formula: (Births minus deaths) plus (in-migration minus out-migration) = Change in population.

The Population Change Index: Projected to Actual (PCI) is an indicator that qualifies the type of growth or decline that has occurred in recent quarters. It is a measure of the comparison between expected and actual. This variable is called Expected Value Index (EVI) by STI.

PCI may take on a value ranging from –2 to +2. The sign represents the direction of the data. A positive means growth and a negative means decline. With respect to a growth situation, a value centering around one indicates that the expected growth and actual growth are essentially equal.

A value between 0 and 1 means actual growth is beginning to taper off (the possible beginnings of a growth plateau). A value between 1 and 2 means growth is accelerating beyond expectations (the possible beginnings of a new growth cycle). A value of zero means no population or NA (Not Applicable). Negative values can be interpreted as the inverse of positive growth.

Categories include:

• >1 Growth accelerating

• 1 = Growth as expected

• >0 to 1 Growth tapering off

• <0 to -1 Decline tapering off

• 1 = Decline as expected

• >-1 Decline accelerating

A community expects growth through residential development, but the PCI indicates to what extent the actual growth or decline conforms to what was expected.

There are three possibilities for growth and three for decline.

• An area may be growing faster than expected, so growth is accelerating. An area's growth may slow down and taper off so that the growth is less than expected, or it can be growing as expected.

• An area may be declining faster than expected, so the decline is accelerating. An area's decline may be slow down and taper off so that the decline is less than expected, or it can be declining just as expected.

• If zero (0) is returned, this means no population

Quarterly history of population change reflects the estimated changes over the prior eight quarters and as of the most recent demographic update.

Data is reported by quarter as a historical trend. The value of this variable is its sensitivity to immediate changes in population. The standard current year estimate and five and 10 year projections provide the longer view but this variable shows more immediate historical changes at a quarter by quarter level.

Seasonal population is defined as population that resides in a housing unit specifically designated as seasonal housing. Unlike regular housing, seasonal housing is used only for a specific season, like a summer cottage or winter chalet. The unit is typically vacant during the other times of the year.

Seasonal housing must not be confused with second homes. Second homes are typically occupied at various times of the year as opposed to being limited to a specific season. Although all seasonal housing might be considered second homes, all second homes are not necessarily seasonal (and therefore, most importantly, not counted in this estimate). It is reported as the average occupancy for the quarter, not daily as the Transient Population.

Seasonal population resides in a location between six weeks and six months. It can include second homes or some migrant housing, though it is not possible to know aside from knowing an area on the ground. For example, in a community that is known to employ migrant workers, seasonal population may reflect that reality. In an area known for vacation homes, it may tip in that direction.

Seasonal Population is determined by looking at quarterly estimates from the Bureau of Labor Statistics. There is a high correlation between certain industries and their hiring practices with the seasonality of an area. This correlation helps determine seasonal population shifts.

Transient population is defined as that population which resides in a hotel, campground, or RV park (Recreational Vehicle) for at least one (1) night or up to six weeks but no more.

This figure is exclusive from all other data in MissionInsite. You will not see this number reflected in any of the breakout variables such as age, income, or ethnic makeup. This value is not a part of the overall population estimate. It is reported as the average daily occupancy for the quarter. Data is reported as a table covering the prior eight (8) quarters.

The estimate is determined based on STI's proprietary model and information from the American Travel Survey (produced by the Bureau of Transportation Statistics), flight statistics from the FAA (Federal Aviation Administration), park attendance from the National Parks Service, and other local/government sources. This is a mathematically determined estimate and not based on direct observation or survey results.

Population by gender refers to a person's sex. Individuals were asked to mark either ''male'' or ''female'' to indicate their sex.

For most cases in which sex was not reported, it was determined from the person's given (i.e., first) name and household relationship. Otherwise, sex was imputed according to the relationship to the householder and the age of the person. Four data points are reported.

Categories reported:

• Female

• Male