1{2 "record_id": "a7a83b631f85316bae926a6c965b325fb26c01c4",3 "eligible": true,4 "exclusion_reason": null,5 "study": {6 "title": "A gamma generalised linear model as an alternative to log linear real estate price functions",7 "year": 2019,8 "doi": "10.4102/jef.v12i1.476",9 "country": "South Africa",10 "region_city": "South Africa (national; >2000 suburb/area factor levels)",11 "sample_start": 2013,12 "sample_end": 2017,13 "property_type": "mixed",14 "price_type": "listing",15 "data_source": "Online property portal aggregating agency listings across South Africa, Jan 2013 - Aug 2017; 415,200 listings after autoencoder anomaly removal; 70% training split",16 "document_type": "journal",17 "estimators": [18 "other"19 ],20 "spatial_method": "none (area factor dummies, >2000 levels)",21 "time_fe": false,22 "location_fe": true,23 "se_type": "unknown",24 "n_obs_total": 415200,25 "ai_methods": [26 "autoencoder (H2O) used only for anomaly detection in data cleaning"27 ],28 "notes": "Yearly cross-sectional gamma GLMs with log link (Table 4, p.9), fitted on the 70% training split; per-year n not printed. Coefficients are interpreted by the authors as percentage effects (beta x 100 %); dep_transform coded 'log' to reflect the log link (E[price]=exp(Xb)), NOT a log-transformed price. Only p-values are printed (no SE/t); p printed as '2e-9' is taken literally (likely a floor of the software output); '4-e5' in 2013 Simplex read as 4e-5. Area (suburb) factor coefficients omitted by the authors. Property-type dummies relative to apartment (reference). Listing price in ZAR (>= 200,000)."29 },30 "models": [31 {32 "model_id": "T4-2013",33 "table": "4",34 "column": "2013",35 "page": 9,36 "dep_var": "listing price (ZAR), gamma GLM log link",37 "dep_transform": "log",38 "estimator": "other",39 "n_obs": null,40 "r2": null,41 "se_or_t_in_parentheses": "p",42 "sample_subset": "Listings of year 2013 (training split 70%); gamma GLM log link; deviance explained 0.89"43 },44 {45 "model_id": "T4-2014",46 "table": "4",47 "column": "2014",48 "page": 9,49 "dep_var": "listing price (ZAR), gamma GLM log link",50 "dep_transform": "log",51 "estimator": "other",52 "n_obs": null,53 "r2": null,54 "se_or_t_in_parentheses": "p",55 "sample_subset": "Listings of year 2014 (training split 70%); gamma GLM log link; deviance explained 0.87"56 },57 {58 "model_id": "T4-2015",59 "table": "4",60 "column": "2015",61 "page": 9,62 "dep_var": "listing price (ZAR), gamma GLM log link",63 "dep_transform": "log",64 "estimator": "other",65 "n_obs": null,66 "r2": null,67 "se_or_t_in_parentheses": "p",68 "sample_subset": "Listings of year 2015 (training split 70%); gamma GLM log link; deviance explained 0.87"69 },70 {71 "model_id": "T4-2016",72 "table": "4",73 "column": "2016",74 "page": 9,75 "dep_var": "listing price (ZAR), gamma GLM log link",76 "dep_transform": "log",77 "estimator": "other",78 "n_obs": null,79 "r2": null,80 "se_or_t_in_parentheses": "p",81 "sample_subset": "Listings of year 2016 (training split 70%); gamma GLM log link; deviance explained 0.87"82 },83 {84 "model_id": "T4-2017",85 "table": "4",86 "column": "2017",87 "page": 9,88 "dep_var": "listing price (ZAR), gamma GLM log link",89 "dep_transform": "log",90 "estimator": "other",91 "n_obs": null,92 "r2": null,93 "se_or_t_in_parentheses": "p",94 "sample_subset": "Listings of year 2017 (training split 70%); gamma GLM log link; deviance explained 0.88"95 }96 ],97 "coefficients": [98 {99 "model_id": "T4-2013",100 "var_name_printed": "Log (size)",101 "taxonomy_id": "living_area",102 "x_transform": "log",103 "x_unit": "m2",104 "beta": 0.664,105 "se": null,106 "t": null,107 "p": 2e-09,108 "p_stars": "",109 "ci_lo": null,110 "ci_hi": null,111 "page": 9,112 "confidence": "high",113 "notes": "natural log of structure size in m2; elasticity; only p-value printed"114 },115 {116 "model_id": "T4-2014",117 "var_name_printed": "Log (size)",118 "taxonomy_id": "living_area",119 "x_transform": "log",120 "x_unit": "m2",121 "beta": 0.626,122 "se": null,123 "t": null,124 "p": 2e-09,125 "p_stars": "",126 "ci_lo": null,127 "ci_hi": null,128 "page": 9,129 "confidence": "high",130 "notes": "natural log of structure size in m2; elasticity; only p-value printed"131 },132 {133 "model_id": "T4-2015",134 "var_name_printed": "Log (size)",135 "taxonomy_id": "living_area",136 "x_transform": "log",137 "x_unit": "m2",138 "beta": 0.558,139 "se": null,140 "t": null,141 "p": 2e-09,142 "p_stars": "",143 "ci_lo": null,144 "ci_hi": null,145 "page": 9,146 "confidence": "high",147 "notes": "natural log of structure size in m2; elasticity; only p-value printed"148 },149 {150 "model_id": "T4-2016",151 "var_name_printed": "Log (size)",152 "taxonomy_id": "living_area",153 "x_transform": "log",154 "x_unit": "m2",155 "beta": 0.479,156 "se": null,157 "t": null,158 "p": 2e-09,159 "p_stars": "",160 "ci_lo": null,161 "ci_hi": null,162 "page": 9,163 "confidence": "high",164 "notes": "natural log of structure size in m2; elasticity; only p-value printed"165 },166 {167 "model_id": "T4-2017",168 "var_name_printed": "Log (size)",169 "taxonomy_id": "living_area",170 "x_transform": "log",171 "x_unit": "m2",172 "beta": 0.512,173 "se": null,174 "t": null,175 "p": 2e-09,176 "p_stars": "",177 "ci_lo": null,178 "ci_hi": null,179 "page": 9,180 "confidence": "high",181 "notes": "natural log of structure size in m2; elasticity; only p-value printed"182 },183 {184 "model_id": "T4-2013",185 "var_name_printed": "Bedrooms",186 "taxonomy_id": "bedrooms",187 "x_transform": "level",188 "x_unit": "count",189 "beta": 0.003,190 "se": null,191 "t": null,192 "p": 0.313,193 "p_stars": "",194 "ci_lo": null,195 "ci_hi": null,196 "page": 9,197 "confidence": "high",198 "notes": "number of bedrooms; only p-value printed"199 },200 {201 "model_id": "T4-2014",202 "var_name_printed": "Bedrooms",203 "taxonomy_id": "bedrooms",204 "x_transform": "level",205 "x_unit": "count",206 "beta": 0.017,207 "se": null,208 "t": null,209 "p": 2e-09,210 "p_stars": "",211 "ci_lo": null,212 "ci_hi": null,213 "page": 9,214 "confidence": "high",215 "notes": "number of bedrooms; only p-value printed"216 },217 {218 "model_id": "T4-2015",219 "var_name_printed": "Bedrooms",220 "taxonomy_id": "bedrooms",221 "x_transform": "level",222 "x_unit": "count",223 "beta": 0.021,224 "se": null,225 "t": null,226 "p": 2e-09,227 "p_stars": "",228 "ci_lo": null,229 "ci_hi": null,230 "page": 9,231 "confidence": "high",232 "notes": "number of bedrooms; only p-value printed"233 },234 {235 "model_id": "T4-2016",236 "var_name_printed": "Bedrooms",237 "taxonomy_id": "bedrooms",238 "x_transform": "level",239 "x_unit": "count",240 "beta": 0.034,241 "se": null,242 "t": null,243 "p": 2e-09,244 "p_stars": "",245 "ci_lo": null,246 "ci_hi": null,247 "page": 9,248 "confidence": "high",249 "notes": "number of bedrooms; only p-value printed"250 },251 {252 "model_id": "T4-2017",253 "var_name_printed": "Bedrooms",254 "taxonomy_id": "bedrooms",255 "x_transform": "level",256 "x_unit": "count",257 "beta": 0.025,258 "se": null,259 "t": null,260 "p": 2e-09,261 "p_stars": "",262 "ci_lo": null,263 "ci_hi": null,264 "page": 9,265 "confidence": "high",266 "notes": "number of bedrooms; only p-value printed"267 },268 {269 "model_id": "T4-2013",270 "var_name_printed": "Bathrooms",271 "taxonomy_id": "bathrooms",272 "x_transform": "level",273 "x_unit": "count",274 "beta": 0.111,275 "se": null,276 "t": null,277 "p": 2e-09,278 "p_stars": "",279 "ci_lo": null,280 "ci_hi": null,281 "page": 9,282 "confidence": "high",283 "notes": "number of bathrooms; only p-value printed"284 },285 {286 "model_id": "T4-2014",287 "var_name_printed": "Bathrooms",288 "taxonomy_id": "bathrooms",289 "x_transform": "level",290 "x_unit": "count",291 "beta": 0.096,292 "se": null,293 "t": null,294 "p": 2e-09,295 "p_stars": "",296 "ci_lo": null,297 "ci_hi": null,298 "page": 9,299 "confidence": "high",300 "notes": "number of bathrooms; only p-value printed"301 },302 {303 "model_id": "T4-2015",304 "var_name_printed": "Bathrooms",305 "taxonomy_id": "bathrooms",306 "x_transform": "level",307 "x_unit": "count",308 "beta": 0.112,309 "se": null,310 "t": null,311 "p": 2e-09,312 "p_stars": "",313 "ci_lo": null,314 "ci_hi": null,315 "page": 9,316 "confidence": "high",317 "notes": "number of bathrooms; only p-value printed"318 },319 {320 "model_id": "T4-2016",321 "var_name_printed": "Bathrooms",322 "taxonomy_id": "bathrooms",323 "x_transform": "level",324 "x_unit": "count",325 "beta": 0.117,326 "se": null,327 "t": null,328 "p": 2e-09,329 "p_stars": "",330 "ci_lo": null,331 "ci_hi": null,332 "page": 9,333 "confidence": "high",334 "notes": "number of bathrooms; only p-value printed"335 },336 {337 "model_id": "T4-2017",338 "var_name_printed": "Bathrooms",339 "taxonomy_id": "bathrooms",340 "x_transform": "level",341 "x_unit": "count",342 "beta": 0.112,343 "se": null,344 "t": null,345 "p": 2e-09,346 "p_stars": "",347 "ci_lo": null,348 "ci_hi": null,349 "page": 9,350 "confidence": "high",351 "notes": "number of bathrooms; only p-value printed"352 },353 {354 "model_id": "T4-2013",355 "var_name_printed": "Cluster",356 "taxonomy_id": "dwelling_type",357 "x_transform": "dummy",358 "x_unit": "binary",359 "beta": 0.09,360 "se": null,361 "t": null,362 "p": 2e-09,363 "p_stars": "",364 "ci_lo": null,365 "ci_hi": null,366 "page": 9,367 "confidence": "high",368 "notes": "cluster home vs apartment (reference); only p-value printed"369 },370 {371 "model_id": "T4-2014",372 "var_name_printed": "Cluster",373 "taxonomy_id": "dwelling_type",374 "x_transform": "dummy",375 "x_unit": "binary",376 "beta": 0.136,377 "se": null,378 "t": null,379 "p": 2e-09,380 "p_stars": "",381 "ci_lo": null,382 "ci_hi": null,383 "page": 9,384 "confidence": "high",385 "notes": "cluster home vs apartment (reference); only p-value printed"386 },387 {388 "model_id": "T4-2015",389 "var_name_printed": "Cluster",390 "taxonomy_id": "dwelling_type",391 "x_transform": "dummy",392 "x_unit": "binary",393 "beta": 0.146,394 "se": null,395 "t": null,396 "p": 2e-09,397 "p_stars": "",398 "ci_lo": null,399 "ci_hi": null,400 "page": 9,401 "confidence": "high",402 "notes": "cluster home vs apartment (reference); only p-value printed"403 },404 {405 "model_id": "T4-2016",406 "var_name_printed": "Cluster",407 "taxonomy_id": "dwelling_type",408 "x_transform": "dummy",409 "x_unit": "binary",410 "beta": 0.187,411 "se": null,412 "t": null,413 "p": 2e-09,414 "p_stars": "",415 "ci_lo": null,416 "ci_hi": null,417 "page": 9,418 "confidence": "high",419 "notes": "cluster home vs apartment (reference); only p-value printed"420 },421 {422 "model_id": "T4-2017",423 "var_name_printed": "Cluster",424 "taxonomy_id": "dwelling_type",425 "x_transform": "dummy",426 "x_unit": "binary",427 "beta": 0.187,428 "se": null,429 "t": null,430 "p": 2e-09,431 "p_stars": "",432 "ci_lo": null,433 "ci_hi": null,434 "page": 9,435 "confidence": "high",436 "notes": "cluster home vs apartment (reference); only p-value printed"437 },438 {439 "model_id": "T4-2013",440 "var_name_printed": "Duplex",441 "taxonomy_id": "dwelling_type",442 "x_transform": "dummy",443 "x_unit": "binary",444 "beta": 0.003,445 "se": null,446 "t": null,447 "p": 0.874,448 "p_stars": "",449 "ci_lo": null,450 "ci_hi": null,451 "page": 9,452 "confidence": "high",453 "notes": "duplex vs apartment (reference); only p-value printed"454 },455 {456 "model_id": "T4-2014",457 "var_name_printed": "Duplex",458 "taxonomy_id": "dwelling_type",459 "x_transform": "dummy",460 "x_unit": "binary",461 "beta": 0.025,462 "se": null,463 "t": null,464 "p": 0.104,465 "p_stars": "",466 "ci_lo": null,467 "ci_hi": null,468 "page": 9,469 "confidence": "high",470 "notes": "duplex vs apartment (reference); only p-value printed"471 },472 {473 "model_id": "T4-2015",474 "var_name_printed": "Duplex",475 "taxonomy_id": "dwelling_type",476 "x_transform": "dummy",477 "x_unit": "binary",478 "beta": 0.035,479 "se": null,480 "t": null,481 "p": 0.024,482 "p_stars": "",483 "ci_lo": null,484 "ci_hi": null,485 "page": 9,486 "confidence": "high",487 "notes": "duplex vs apartment (reference); only p-value printed"488 },489 {490 "model_id": "T4-2016",491 "var_name_printed": "Duplex",492 "taxonomy_id": "dwelling_type",493 "x_transform": "dummy",494 "x_unit": "binary",495 "beta": 0.086,496 "se": null,497 "t": null,498 "p": 2e-09,499 "p_stars": "",500 "ci_lo": null,501 "ci_hi": null,502 "page": 9,503 "confidence": "high",504 "notes": "duplex vs apartment (reference); only p-value printed"505 },506 {507 "model_id": "T4-2017",508 "var_name_printed": "Duplex",509 "taxonomy_id": "dwelling_type",510 "x_transform": "dummy",511 "x_unit": "binary",512 "beta": 0.079,513 "se": null,514 "t": null,515 "p": 2e-09,516 "p_stars": "",517 "ci_lo": null,518 "ci_hi": null,519 "page": 9,520 "confidence": "high",521 "notes": "duplex vs apartment (reference); only p-value printed"522 },523 {524 "model_id": "T4-2013",525 "var_name_printed": "House",526 "taxonomy_id": "dwelling_type",527 "x_transform": "dummy",528 "x_unit": "binary",529 "beta": 0.027,530 "se": null,531 "t": null,532 "p": 0.0003,533 "p_stars": "",534 "ci_lo": null,535 "ci_hi": null,536 "page": 9,537 "confidence": "high",538 "notes": "house vs apartment (reference); only p-value printed"539 },540 {541 "model_id": "T4-2014",542 "var_name_printed": "House",543 "taxonomy_id": "dwelling_type",544 "x_transform": "dummy",545 "x_unit": "binary",546 "beta": 0.063,547 "se": null,548 "t": null,549 "p": 2e-09,550 "p_stars": "",551 "ci_lo": null,552 "ci_hi": null,553 "page": 9,554 "confidence": "high",555 "notes": "house vs apartment (reference); only p-value printed"556 },557 {558 "model_id": "T4-2015",559 "var_name_printed": "House",560 "taxonomy_id": "dwelling_type",561 "x_transform": "dummy",562 "x_unit": "binary",563 "beta": 0.103,564 "se": null,565 "t": null,566 "p": 2e-09,567 "p_stars": "",568 "ci_lo": null,569 "ci_hi": null,570 "page": 9,571 "confidence": "high",572 "notes": "house vs apartment (reference); only p-value printed"573 },574 {575 "model_id": "T4-2016",576 "var_name_printed": "House",577 "taxonomy_id": "dwelling_type",578 "x_transform": "dummy",579 "x_unit": "binary",580 "beta": 0.158,581 "se": null,582 "t": null,583 "p": 2e-09,584 "p_stars": "",585 "ci_lo": null,586 "ci_hi": null,587 "page": 9,588 "confidence": "high",589 "notes": "house vs apartment (reference); only p-value printed"590 },591 {592 "model_id": "T4-2017",593 "var_name_printed": "House",594 "taxonomy_id": "dwelling_type",595 "x_transform": "dummy",596 "x_unit": "binary",597 "beta": 0.141,598 "se": null,599 "t": null,600 "p": 2e-09,601 "p_stars": "",602 "ci_lo": null,603 "ci_hi": null,604 "page": 9,605 "confidence": "high",606 "notes": "house vs apartment (reference); only p-value printed"607 },608 {609 "model_id": "T4-2013",610 "var_name_printed": "Simplex",611 "taxonomy_id": "dwelling_type",612 "x_transform": "dummy",613 "x_unit": "binary",614 "beta": 0.061,615 "se": null,616 "t": null,617 "p": 4e-05,618 "p_stars": "",619 "ci_lo": null,620 "ci_hi": null,621 "page": 9,622 "confidence": "high",623 "notes": "simplex vs apartment (reference); p printed as '4-e5' (typo), read as 4e-5; only p-value printed"624 },625 {626 "model_id": "T4-2014",627 "var_name_printed": "Simplex",628 "taxonomy_id": "dwelling_type",629 "x_transform": "dummy",630 "x_unit": "binary",631 "beta": 0.068,632 "se": null,633 "t": null,634 "p": 5e-07,635 "p_stars": "",636 "ci_lo": null,637 "ci_hi": null,638 "page": 9,639 "confidence": "high",640 "notes": "simplex vs apartment (reference); only p-value printed"641 },642 {643 "model_id": "T4-2015",644 "var_name_printed": "Simplex",645 "taxonomy_id": "dwelling_type",646 "x_transform": "dummy",647 "x_unit": "binary",648 "beta": 0.078,649 "se": null,650 "t": null,651 "p": 2e-09,652 "p_stars": "",653 "ci_lo": null,654 "ci_hi": null,655 "page": 9,656 "confidence": "high",657 "notes": "simplex vs apartment (reference); only p-value printed"658 },659 {660 "model_id": "T4-2016",661 "var_name_printed": "Simplex",662 "taxonomy_id": "dwelling_type",663 "x_transform": "dummy",664 "x_unit": "binary",665 "beta": 0.117,666 "se": null,667 "t": null,668 "p": 2e-09,669 "p_stars": "",670 "ci_lo": null,671 "ci_hi": null,672 "page": 9,673 "confidence": "high",674 "notes": "simplex vs apartment (reference); only p-value printed"675 },676 {677 "model_id": "T4-2017",678 "var_name_printed": "Simplex",679 "taxonomy_id": "dwelling_type",680 "x_transform": "dummy",681 "x_unit": "binary",682 "beta": 0.087,683 "se": null,684 "t": null,685 "p": 2e-09,686 "p_stars": "",687 "ci_lo": null,688 "ci_hi": null,689 "page": 9,690 "confidence": "high",691 "notes": "simplex vs apartment (reference); only p-value printed"692 },693 {694 "model_id": "T4-2013",695 "var_name_printed": "Townhouse",696 "taxonomy_id": "dwelling_type",697 "x_transform": "dummy",698 "x_unit": "binary",699 "beta": 0.05,700 "se": null,701 "t": null,702 "p": 0.064,703 "p_stars": "",704 "ci_lo": null,705 "ci_hi": null,706 "page": 9,707 "confidence": "high",708 "notes": "townhouse vs apartment (reference); only p-value printed"709 },710 {711 "model_id": "T4-2014",712 "var_name_printed": "Townhouse",713 "taxonomy_id": "dwelling_type",714 "x_transform": "dummy",715 "x_unit": "binary",716 "beta": 0.063,717 "se": null,718 "t": null,719 "p": 2e-09,720 "p_stars": "",721 "ci_lo": null,722 "ci_hi": null,723 "page": 9,724 "confidence": "high",725 "notes": "townhouse vs apartment (reference); only p-value printed"726 },727 {728 "model_id": "T4-2015",729 "var_name_printed": "Townhouse",730 "taxonomy_id": "dwelling_type",731 "x_transform": "dummy",732 "x_unit": "binary",733 "beta": 0.077,734 "se": null,735 "t": null,736 "p": 2e-09,737 "p_stars": "",738 "ci_lo": null,739 "ci_hi": null,740 "page": 9,741 "confidence": "high",742 "notes": "townhouse vs apartment (reference); only p-value printed"743 },744 {745 "model_id": "T4-2016",746 "var_name_printed": "Townhouse",747 "taxonomy_id": "dwelling_type",748 "x_transform": "dummy",749 "x_unit": "binary",750 "beta": 0.09,751 "se": null,752 "t": null,753 "p": 2e-09,754 "p_stars": "",755 "ci_lo": null,756 "ci_hi": null,757 "page": 9,758 "confidence": "high",759 "notes": "townhouse vs apartment (reference); only p-value printed"760 },761 {762 "model_id": "T4-2017",763 "var_name_printed": "Townhouse",764 "taxonomy_id": "dwelling_type",765 "x_transform": "dummy",766 "x_unit": "binary",767 "beta": 0.099,768 "se": null,769 "t": null,770 "p": 2e-09,771 "p_stars": "",772 "ci_lo": null,773 "ci_hi": null,774 "page": 9,775 "confidence": "high",776 "notes": "townhouse vs apartment (reference); only p-value printed"777 }778 ]779}