LISTSERV at the University of Georgia
Menubar Imagemap
Home Browse Manage Request Manuals Register
Previous (more recent) messageNext (less recent) messagePrevious (more recent) in topicNext (less recent) in topicPrevious (more recent) by same authorNext (less recent) by same authorPrevious page (March 2002)Back to main SPSSX-L pageJoin or leave SPSSX-L (or change settings)ReplyPost a new messageSearchProportional fontNon-proportional font
Date:         Thu, 21 Mar 2002 11:23:20 -0300
Reply-To:     hmaletta@fibertel.com.ar
Sender:       "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From:         Hector Maletta <hmaletta@fibertel.com.ar>
Subject:      Re: extrapolation help required!
Comments: To: Lisel O'Dwyer <lisel.odwyer@flinders.edu.au>
Content-Type: text/plain; charset=us-ascii

Lisel, interpolating for the intervening years, however it is done, assumes a continuous adjustment of rent. Is that actually so? Unless some adjustment or indexation clause is included, rental contracts usually remain fixed for the duration. I do not know whether contracts of this sort are annual, or for two years, or what. Even when you have a new contract with a new rental price (contract T+1 in your parlance), you don't know whether the previous tenant ended up paying the same amount agreed upon at the beginning of the contract, or got his rent adjusted to reflect the changing market price.

All this regards rent paid, in nominal terms. You may have other purposes in mind. For instance, you may ask: "This house was rented for $1000 a month in the year 1998; how much would it be rented for in 1999?" If the house remained occupied by the same tenant from 1998 to later years, with an unchanged contract, you won't have an actual contract made in 1999 to answer your question with precision, so you'd have to estimate an answer. This answer you may find by looking at the general evolution of rental prices in the relevant area (and type of housing) from 1998 to 1999. For this you would need a price index of housing, that you wopuld apply to the original rent agreed for that house in past years and thence estimate the "price" in 1999. That would be only an estimate of course, based on other dwellings and not the one you're interested in. Estimating price indexes for housing rent is actually one of the most difficult problems in the field of price indexes. All statistical boards in the world (including the Australian one I'm sure) have come up with some solution, as has the BLS in the US.- In the BLS Web site there are some references to papers written by BLS staff on this matter.

Hector Maletta Universidad del Salvador Buenos Aires, Argentina

Lisel O'Dwyer wrote: > > Hi all > > does anyone have any bright ideas on how to do the following...?! > > I have a dataset of N records of rental properties' rental histories over > the last 10 years - the dates the property was let to a new tenant, how > long the lease lasted and the value of rent paid at the *outset* of the > tenancy. I want to calculate/estimate what the value of the rent was at the > *end* of the tenancy. Since rents (in Australia!) have not increased at the > same rate as inflation, I cannot simply multiply by inflation. > > Instead, I have assumed that the rent at the end of a tenancy T is the same > as the rent recorded for the beginning of tenancy T +1. Then I can work out > what the rent was during tenancy T after one, two or X years of a tenancy of > length Y years. > > This works out fine for records where a property was let more than once over > the 10 year period. > > The trouble is for properties which were let only once, say, in 1992 for 5 > years (ie the lease was completed in 1997) but then the property was not let > again. How can I estimate what the rent in 1993-1997 was? I think it must > be something to do with interpolating/extrapolating based on the end rent > values of dwellings with similar characteristics, (eg location, dwelling > structure, number of bedrooms, let in the same year) but which were let more > than once. > > But how do I do that? > > Thanks in advance!!!! > > Lisel > > Dr Lisel O'Dwyer > > School of Geography, Population and Environmental Management > Flinders University > GPO Box 2100 > Adelaide, South Australia 5001 > http://www.ssn.flinders.edu.au/geog/staff/odwyer.htm > IAG home page: http://www.ssn.flinders.edu.au/geog/iag/ > Telephone 61 8 8201 2969 > Fax 61 8 8201 3521


Back to: Top of message | Previous page | Main SPSSX-L page